Tetrapods: Out on a limb

Tetrapods: An Introduction

What exactly are tetrapods? How did they evolve in a way that enabled them to live out of water? What classes of tetrapods can we see today?

Discovering Tetrapods: The Remarkable Journey from Water to Land

The history of life on Earth is filled with pivotal moments, but few are as significant as the transition of vertebrates from aquatic environments to solid ground. This monumental leap was made possible by the evolution of tetrapods, a superclass of vertebrates that includes some of the most diverse and familiar animals on the planet: amphibians, reptiles, birds, and mammals. Their success story is a powerful example of adaptation and has profoundly shaped terrestrial ecosystems.

What Defines a Tetrapod?

At its core, a tetrapod is a vertebrate animal. The name itself comes from the Greek words "tetra" (four) and "pous" (foot). While the name implies "four-footed," the defining characteristic is possessing four limbs or being descended from ancestors that had four limbs. Even animals like snakes and whales, which have lost or modified their limbs, are classified as tetrapods because of their evolutionary history and skeletal structure. Birds, for instance, possess wings and legs.

The Evolutionary Leap: Leaving the Water

Tetrapods first emerged approximately 360 million years ago during the Devonian period. They evolved from a group of fish known as lobe-finned fishes. These early fish had fleshy, limb-like fins with bones that allowed them to support their bodies. Over millions of years, these fins gradually transformed into limbs with digits, enabling movement on land.

The fossil record provides compelling evidence of this transition, with creatures like Ichthyostega and Acanthostega from the Late Devonian period (around 370-360 million years ago) serving as crucial transitional forms. These animals still retained some fish-like features but also showed clear signs of developing limbs. The prevailing hypothesis suggests that early tetrapods ventured onto land not necessarily to escape drying water, but perhaps to exploit new food sources or escape aquatic predators in shallow, potentially oxygen-poor, environments. This ability to manoeuvre in shallow water and on land would have provided a significant advantage. Beyond the limbs, tetrapods developed other adaptations for terrestrial life, including lungs for breathing air, a strengthened vertebral column, and modifications to their circulatory and nervous systems.

A Spectacular Diversification

Once established on land, tetrapods underwent a rapid and widespread diversification. Today, the main classes are:

• Amphibia: This is the most ancient lineage of extant tetrapods. Examples include frogs and salamanders. Amphibians often begin life as aquatic larvae and are still intimately tied to water for reproduction, typically laying eggs in aquatic environments. Their moist skin also aids respiration but requires them to stay in damp habitats.
• Reptilia: This class includes lizards, snakes, and crocodiles. Reptiles were the first tetrapods to fully colonise land. They possess key adaptations like dry, scaly skin that minimises water loss and, crucially, the ability to lay amniotic eggs with shells. The amniotic egg was a major evolutionary innovation. This protective egg allowed reproduction away from water, containing the developing embryo within membranes and its own food supply. Reptiles are also ectothermic, relying on external heat sources for temperature regulation.
• Aves (Birds): Birds are uniquely characterised by the presence of feathers. They evolved from reptilian ancestors, specifically feathered dinosaurs. Adaptations like lightweight skeletons and wings enabled flight in many species. Birds are endothermic (warm-blooded) with high metabolic rates. Examples include eagles and penguins.
• Mammalia: Mammals are defined by hair or fur and mammary glands that produce milk to nourish their young. Like birds, mammals are endothermic (warm-blooded). While most give birth to live young, a few primitive species, like the platypus, still lay eggs. Mammals evolved from early reptile-like ancestors known as synapsids. Examples include humans, dogs, and whales.

An Enduring Legacy

With over 30,000 species today, tetrapods have adapted to nearly every environment on the planet. Their evolution from water-dwelling fish to the diverse array of terrestrial, aerial, and even secondarily aquatic vertebrates we see today represents a remarkable evolutionary journey. Understanding the origins and diversification of tetrapods provides vital insights into the history of vertebrate life and highlights the deep evolutionary connections among all animals—including ourselves. The versatility of the tetrapod body plan is a testament to the power of adaptation.

Mammals: Nature’s Warm-Blooded Wonders

What are the characteristics of mammal species? What are the main groups of mammals? What mammals have been seen in the Sidmouth area?

Mammals are one of the most diverse and fascinating groups in the animal kingdom. Whether running, flying, swimming, or burrowing, mammals have adapted to nearly every environment on Earth. Mammals play vital roles in nearly every ecosystem on the planet. From pollinating plants to controlling insect populations, their presence is crucial for maintaining ecological balance. Understanding mammals also helps us appreciate our own place in the natural world, as humans are, of course, mammals too. Mammals play critical roles in ecosystems around the world. As top predators, scavengers, grazers, and prey, mammals keep nature’s balance in check.

What Makes a Mammal a Mammal?

Mammals are a class of animals characterised by several key features that set them apart. They are vertebrate animals known for a few key characteristics. While their appearances vary wildly, all mammals share a set of key characteristics that set them apart from other animal groups.

Key characteristics include:

• Mammary glands in females, which produce milk to nourish their young. This is perhaps the defining characteristic. This allows mothers to provide essential nutrients and antibodies, giving their offspring a strong start in life.
• A body covering of hair or fur for insulation. This is perhaps the most recognizable trait. Hair or fur helps mammals regulate their body temperature – a crucial adaptation for surviving in a wide range of climates. Hair or fur is present at least at some stage of life.
• A specialised jaw structure containing three middle ear bones, which aids in hearing.
• Warm-bloodedness (endothermy). Mammals are endothermic, meaning they can generate their own body heat. This allows them to remain active even in cold environments, unlike cold-blooded animals that rely on external sources of heat. They regulate their body temperature internally.
• Giving birth to live young (viviparous) in the vast majority of cases. However, there are a few exceptions, like the platypus and echidna, which lay eggs – these are known as monotremes.
• Specialised teeth. Mammals possess a variety of teeth shapes and sizes, adapted for different diets. Whether they're carnivores, herbivores, or omnivores, their teeth are perfectly suited for tearing, grinding, or crushing their food.
• A four-chambered heart. Like birds, mammals have a four-chambered heart that efficiently pumps oxygenated blood throughout their bodies, supporting their high metabolic rate.These traits set mammals apart from other animal groups like reptiles, birds, and amphibians.

Mammal Diversity and Evolution

Mammals evolved from synapsid reptiles during the late Triassic period, approximately 220 million years ago. There are around 6,500 species of mammals today. The class Mammalia is broadly divided into three main groups:

• Monotremes: Egg-laying mammals like the platypus and echidna. These are truly unique.
• Marsupials: Pouched mammals such as kangaroos, koalas, and opossums. They give birth to underdeveloped young that complete their development in a pouch.
• Placental mammals: The most diverse group, including humans, dogs, whales, elephants, and more. They nourish their young in the uterus through a placenta.

Mammals range from solitary mountain lions to highly social elephants and primates. Some live in oceans, others in deserts, forests, or even cities. Mammals occupy a vast array of ecological niches and perform numerous vital roles within ecosystems. They function as predators, controlling populations of other animals; herbivores, influencing plant communities; scavengers, recycling nutrients from dead organisms; pollinators, aiding in plant reproduction; seed dispersers, contributing to the spread of plant species; and ecosystem engineers, physically altering their environment to benefit themselves and other species.

Mammals have evolved a remarkable diversity of adaptations to thrive in nearly every habitat on Earth. Aquatic mammals like dolphins and seals possess streamlined bodies and flippers for efficient swimming. Terrestrial mammals such as big cats have powerful limbs, sharp claws, and keen senses for hunting. Others have developed adaptations for extreme temperatures, arboreal life, or burrowing underground, showcasing the incredible adaptability of this class.

Mammals in the Sidmouth Area

Mammals are found in a variety of habitats across the Sid Valley, including woodland, grassland, hedgerows, scrub, brownfield sites, gardens, and urban areas. They are considered part of the wildlife that benefits from conservation efforts aimed at creating biodiversity networks and corridors, linking isolated habitats. Recording and surveying mammal populations are vital parts of conservation activity, helping to understand what wildlife is present and whether conservation actions are effective.

The Sidmouth Nature project has recorded a relatively low number of mammal species compared to the UK as a whole. The project's surveys recorded six species out of over 100 UK species. This low number is likely due to several factors related to the project's survey methods and the characteristics of the local environment. Firstly, surveys are conducted during the day, while many mammal species are nocturnal. Secondly, mammals are often wary of humans and may avoid detection. Thirdly, the project focuses on specific sites, potentially missing species that inhabit different or inaccessible habitats, such as marine mammals. Additionally, the standard transect survey method used is not specifically designed for detecting many mammal species, which often require specialised techniques like trapping or bat detectors.

However, there are other indications of mammal presence beyond the formal surveys. While the formal Sidmouth Nature project surveys have recorded only six species, an additional six species have been documented on the iNaturalist database since the start of 2020. This brings the total recorded to twelve species, suggesting that more mammals are present in the wider area than the project's focused surveys alone indicate.

Beyond survey limitations, the landscape of the Sidmouth area, dominated by housing, likely plays a significant role in limiting mammal diversity. The amount of suitable habitat for wildlife is reduced and often fragmented into small, isolated patches that may not be large enough to support viable populations of many species. The apparent lack of significant populations of small mammal predators like kestrels and owls also suggests potentially lower numbers of their prey species.

The relatively low recorded mammal diversity in the Sidmouth area may indicate limitations in habitat availability, connectivity, and potentially overall ecosystem health. Understanding mammal diversity is important for conservation efforts. It allows us to identify areas that may require habitat restoration or management to support a wider range of wildlife and maintain healthy, functioning ecosystems for the benefit of both nature and people.

Specific Mammal Species and Groups in the Sid Valley

Surveys and observations have documented several mammal species in the Sid Valley.

• Bats: All 17 UK bat species can be found in or around woodlands, and some are woodland specialists. Bats are a highly protected species. They emerge from hibernation in warmer evenings, needing to feed after winter. Females form maternity colonies in late spring, often on building roofs. Bats are insectivores, many feeding on moths. They use linear features in the landscape, such as hedges, as navigational aids and foraging sites. Common and Soprano Pipistrelles and Daubenton's bats may be seen foraging over the River Sid in The Byes. Greater Horseshoe bats have been recorded in The Byes and on the cliffs. 16 bat species are resident in Devon, and it is possible that woodland species like Bechstein's and Barbastelles are present in the valley. Brown Long Eared, Greater Horseshoe, Serotine, and Whiskered species are seen in the valley. Bats hibernate in tree fissures, caves, tunnels, and cellars, seeking moist, stable, cool temperatures. Bats hunt across The Knapp, including Pipistrelles, Serotines, Noctules, and Lesser Horseshoe Bats. The rare Lesser Horseshoe Bat roosts nearby Knowle and uses the Knapp and cemetery hedges for foraging and commuting. Bats benefit from mature, spreading hedgerows and the long grass around them. Surveys at The Donkey Sanctuary recorded at least 11 species of bat, including lesser and greater horseshoe bats and barbastelle. Bats exploit buildings as surrogate caves.
• Badgers: Badger activity, such as snuffle holes dug to find invertebrates, is noticeable after winter. They feed on worms, beetles, and leatherjackets. Large areas of turf may be ripped up as they search for food that has risen to the surface of sodden ground. Most cubs are born in early spring. Badgers have vast setts in sandy soil, which they are always extending. They use bluebell straw for bedding, brought out to air outside the sett entrances. Their presence can be identified by tracks and circular paths around trees. Claw marks may be found on stones on banks of 'up and overs'. Badger pathways are used by other animals like rabbits, foxes, and deer. Latrines are used to mark territories. Badgers are seen in town. In winter, they are deep in their setts, hiding from the cold and blocking entrances with twigs and leaves. Badgers are found in The Knapp.
• Dormice (Hazel Dormouse): The Hazel Dormouse is mentioned as suffering greatly from intensive agricultural practices and development in the 1960s, with Devon remaining a stronghold. They hibernate in winter. This elusive animal is generally nocturnal and rests in torpor during the day. They are arboreal, spending little time on the ground except when hibernating in nests built at the base of hazel trees. Dormice get their name from their foraging on hazelnuts, and their gnawing technique on nuts is identifiable. They also eat a wide variety of fruits and nectar. They are present in and around Core Hill woodland and are probably quite common across the valley due to the rich tapestry of hedgerows and woodlands, which is their preferred habitat. Dormice were recently found in old hedges running through The Knapp. They depend on hazel, bramble, honeysuckle, elder, ash, and even insects from surrounding meadows. Dormice benefit from mature, spreading hedgerows and the long grass around them.
• Otters: Otters are among the species that suffered decline in the 1960s, with Devon serving as a stronghold. They are one of Britain's top carnivores. They are large (80-150 cm), with webbed feet, grey-brown fur, and a cream underside. Their diet is mainly fish, but also includes birds, frogs, insects, and crustaceans. They close their ears and noses when underwater. Otters live in an underground den called a holt. They have an average territory of 10 miles and are mostly nocturnal. Their numbers fell dramatically following the introduction of pesticides like DDT in the mid-1950s. Otters and their holts are now protected by law. Devon has been one of their strongholds, and they are regularly seen on the River Sid; it is possible to see them in The Byes. Look for their tracks in the silty sand along river banks and under bridges; an adult print is typically about 5.5 cm across.
• Harvest Mice: Harvest mice are mentioned as an increasingly rare mammal species. A colony lives on Mutter's Moor. They are our smallest rodent and second smallest mammal after the Pygmy Shrew. They are distinguished by their hairy ears, reddish adult fur, and remarkable prehensile tails. Most live in areas of long grass, building nests in tussocks of Purple Moor Grass. Harvest mice are secretive and sensitive to footsteps. Females weave round breeding nests about 30 cm above the ground within tussocks. Population estimates are difficult due to their secretive nature. Harvest mice on Mutter's Moor are monitored by the Devon Mammal Group. A harvest mouse nest was found in the Roncombe Valley.
• Shrews: Small mammals mentioned include Pygmy and Common shrews. The Pygmy Shrew is the second smallest mammal after the Harvest Mouse. Shrews are seen scurrying around. Shrews are protected species. They are not rodents, but related to moles, with a distinguishable pointed snout. Shrews need to eat continuously.
• Rodents (General): Besides Harvest Mice, other small rodents mentioned include wood mice and bank voles. These small mammals provide a food source for birds of prey and other carnivores. Bank voles and grey squirrels eat hazelnuts. The Grey Squirrel is a non-native invasive species, present in Britain since 1876. They carry the squirrel pox virus, which has wiped out Devon's red squirrels. Rodents are mentioned as benefitting from the Donkey Sanctuary land.
• Deer: Deer eat beech nuts. They are seen along fields adjacent to woodland. The Roe deer has a high population in the valley and can be seen morning or evening. Deer use badger pathways. Deer are palatable to grazers.
• Foxes: Foxes are seen along fields adjacent to woodland and in town. They eat almost anything. Look out for their X-shaped track. Foxes are predators of birds. Foxes are found in The Knapp. They use badger pathways.
• Rabbits: Rabbits are described as fearless at the Knowle parkland, seen grazing all day and all year round. They use badger pathways. Rabbits are common on sand dunes because the sand is easy to burrow into. Their burrowing can cause 'blow outs', interrupting succession. Their grazing and latrines influence the types of plant species present. Rabbits were traditionally associated with heaths. Their numbers were reduced by myxomatosis.
• Stoats and Weasels: These carnivores feed on small mammals. They are found predominantly in the upper reaches of the valley. They are also predators of birds.
• American Mink: The American Mink is a non-native invasive species that feeds on small mammals. They are voracious predators and are thought to have been the "last straw" for the water vole, which has not been present in the Sid Valley probably since the 1980s.

Mammals and Their Habitats in Sid Valley

Mammals inhabit various environments across the Sid Valley, each offering different resources and challenges.

• Woodlands: Woodlands are rich habitats for mammals. Bats hibernate and roost in trees. Hazel Dormice use woodland for hibernation nests. Deer and foxes are seen along fields adjacent to woodland. Small mammals like wood mice and bank voles are present. Woodlands at the Donkey Sanctuary support mammals.
• Grasslands: Grasslands, particularly traditionally managed ones, are important for small mammals. Mammals like rodents and insectivores benefit from the diverse invertebrate populations supported by grazing. Grazing animals directly impact grassland composition and structure. Rabbits are found in parkland grassland.
• Hedgerows: Devon's banked hedges are important wildlife havens and play a vital role as wildlife corridors. Many common species of mammals are found in hedgerows. Mammal runs, burrows, and feeding signs can be looked for. Bats use hedges as navigational aids and foraging sites. Dormice use hedgerows as preferred habitat and may move through hedges. The cemetery hedges are important for bats, including the Lesser Horseshoe Bat, and dormice have been found there.
• Scrub: Scrub provides important habitat. Common species of mammals can be found in scrub. Dormice may build summer nests in bramble scrub on woodland margins. Scrub on cliff sections may support mammals.
• Urban/Gardens/Brownfield: Wildlife exploits the urban environment. Foxes and badgers can be seen in town. Roe deer are seen on parklands. Rabbits are fearless on parkland. Gardens are important for wildlife, benefiting mammals. Hedgehogs are in need of support in the urban environment and gardens. Fenced gardens reduce habitat for hedgehogs. Bats exploit buildings as surrogate caves. Brownfield sites can be ideal habitat for bats. Churchyards can also be important for wildlife, including bats and possibly dormice.
• Heathland: Lowland heaths, like Fire Beacon Hill and Mutter's Moor, are rare and important habitats. Harvest mice have a colony on Mutter's Moor. Mammals like deer, voles, and shrews may be occasional visitors from surrounding woodland or pasture. Bats can successfully colonise heathlands if bat boxes are provided.
• Coastal Habitats: Sand dunes can be explored; rabbits are common there. Mammals may potentially be in scrub communities and cliff sections. Seals may be disturbed on hard and soft shores by recreation.
• Freshwater/Riparian: Otters are found on the River Sid and in The Byes. Bats forage over the River Sid. Water voles are not present in the Sid Valley, possibly due to American Mink. Mammals are implied to be present in wider aquatic and riparian habitats.

Threats, Conservation, and What You Can Do

Mammal populations face significant threats. Habitat loss and changes in land management practices, such as intensive agriculture and building development, have negatively impacted mammals, including the otter, dormouse, and water vole. The loss of hedgerows due to larger fields for machinery affected mammals that use them as refuges and corridors. Modern grassland management leads to less diverse non-grass species, impacting the fauna that depend on them. Invasive non-native species like the American mink have impacted native species like the water vole, and grey squirrels have impacted red squirrels. Fenced gardens reduce habitat availability for hedgehogs. Pesticides like DDT caused dramatic declines in otters.

Conservation efforts involve habitat restoration and management. These include hedge replacement, coppicing woodland, creating glades and rides, managing scrub, planting trees and hedges, hedgelaying, and appropriate grazing. Creating biodiversity networks and corridors is a strategy to help mammal populations. Specific sites like The Knapp and The Donkey Sanctuary are managed to promote wildlife diversity, including for mammals. Managing gardens for wildlife by providing food, shelter, and avoiding chemicals also supports mammals.

Reptiles: Ancient Lineage, Vital Roles, and Local Challenges

What are the main features of reptiles? What families of reptiles are there? What reptile species can be found in the Sidmouth area?

From slithering snakes to sunbathing lizards, reptiles are some of the oldest and most intriguing animals on Earth. With their scaly skin, slow metabolism, and ancient lineage, these creatures offer a fascinating glimpse into the evolutionary past and a vital role in today’s ecosystems. Reptiles have been around for over 300 million years, showcasing remarkable resilience and adaptability.

What Makes a Reptile a Reptile?

Reptiles are a class of vertebrates (Reptilia) or "cold-blooded" vertebrates that typically lay eggs and are covered in dry, scaly skin. They are ectothermic, meaning they rely on external heat sources to regulate their body temperature. This is why you often see lizards basking in the sun or snakes warming themselves on rocks. Unlike mammals and birds, reptiles do not regulate their body temperature internally. Their bodies are typically covered in scales or scutes, made of keratin, which provide protection, reduce water loss, and can aid in camouflage.

Most reptiles reproduce by laying amniotic eggs. These eggs have membranes that protect and nourish the embryo, allowing development on land without drying out. This was a significant evolutionary step for vertebrates. All reptiles breathe air using lungs. While snakes are limbless, reptiles are characterised as having four limbs or being descended from four-limbed ancestors. They belong to the class Reptilia and are vertebrates, meaning they have a backbone.

A Journey Through Reptilian Diversity

The major groups of reptiles include snakes (serpentes), turtles (testudines), crocodilians (crocodylia), lizards (squamata), and the tuatara (sphenodontia). These groups encompass a vast diversity of species. The world of reptiles is incredibly rich, encompassing four main living orders:

• Squamata (Lizards and Snakes): This is the largest order with over 10,000 species. Lizards are varied, while snakes are limbless predators known for their unique locomotion and, in some cases, venom.
• Testudines (Turtles and Tortoises): Characterised by their protective bony shell, they are ancient reptiles. Turtles are generally aquatic or semi-aquatic, while tortoises are terrestrial.
• Crocodylia (Crocodiles, Alligators, Caimans, and Gharials): These are the largest living reptiles and are semi-aquatic predators found in tropical and subtropical regions. They are known for their powerful jaws and ancient lineage. Crocodilians are especially close relatives of ancient species that once ruled the planet.
• Rhynchocephalia (Tuataras): This order contains only two species, found exclusively in New Zealand. Often called "living fossils," they are the sole survivors of a group that flourished alongside the dinosaurs.

Reptiles exhibit a wide range of remarkable adaptations that enable them to survive in diverse environments. Their ectothermic metabolism allows them to thrive in both hot and cold climates by adjusting their behaviour to utilise external heat sources. Other adaptations include specialised venom-delivery systems in snakes, protective shells of turtles, powerful jaws and acute senses of crocodilians, and the ability of some lizards to shed their tails.

Global Diversity and British Fauna

Globally, there are over 10,000 recognised species of reptiles inhabiting nearly every continent and a wide array of habitats. Reptiles are incredibly adaptable, living in deserts, forests, wetlands, and even oceans. Some, like geckos, climb vertical walls, while sea turtles migrate across entire oceans.

In contrast, Britain has a very limited native reptile fauna due to its climate, with only six native species: three snakes and three lizards.

Reptiles in the Sidmouth Area

The Sid Valley provides habitats for several reptile species. According to the sources, reptiles like the sandy soils of the heathland, which is described as a vital habitat for reptiles. Lowland dry heath habitats can potentially host all six native British reptile species. Brownfield sites can also be ideal habitats for several species.

In the Sidmouth area specifically, the situation is even more restricted. Of the six native British species, only four have been recorded:

• Adder (Vipera berus): Mentioned as liking sandy soils of heathland. They awaken from hibernation and can be seen basking on bare sandy earth. Adders are Britain's only venomous snake, recognised by the zig-zag pattern down their back and vertical pupil. They often lay still and show no aggression in dense vegetation. Males are usually grey/cream, females brown, yellow, or orange-red and larger. They overwinter in hibernacula, sometimes with up to 25 individuals. Females breed only every 3-4 years, producing ginger juveniles. Adders are one of the six native species found on heathland and brownfield sites.
• Grass Snake (Natrix natrix): More likely found along slow-moving water and ponds. They can grow over 1 meter long and are not venomous. Recognised by a yellow and black collar behind the head and olive green with black spots/stripes. They hunt fish, newts, frogs, and toads, often seen in the daytime. Included in the list of six native species found on heathland and brownfield sites.
• Common Lizard (Lacerta vivipara): Found on heathland, awakening from hibernation and basking. They can be seen basking on pathways, best found on warm south-facing slopes. They scurry quickly into undergrowth when approached. Listed as one of the six native species found on heathland and brownfield sites. In the lower section of Sidmouth Cemetery, lizards (with slow worms) find refuge amongst warm stones.
• Slow Worm (Anguis fragilis): Described as legless lizards. Can be seen basking on stone piles. Also found in and around town, especially in compost heaps and under objects. Females are varied in colour (pale grey-cream to metallic copper with darker flanks), older males sometimes have blue spots. Distinguished from snakes by head shape and have a docile manner. Listed as one of the six native species found on heathland and brownfield sites. In Sidmouth Cemetery, slow worms (with lizards) find refuge amongst warm stones. They are among the few mammals that truly hibernate in the valley (along with bats and dormice).

Of these four species recorded in the Sidmouth area, none are common. Notably, only the slow-worm has been observed in Sidmouth Nature surveying activities, and that was a deceased individual.

Crucial Ecological Roles

Though they’re often misunderstood, reptiles play crucial roles in food chains—both as predators and prey. They play vital roles in maintaining the balance and health of ecosystems. As predators, they help regulate populations of their prey, preventing any single species from becoming dominant. They also serve as important prey for various other animals, forming integral links in food webs. Some reptiles act as ecosystem engineers; for instance, crocodiles maintain waterholes that provide resources during dry periods, and turtles can influence aquatic vegetation and contribute to nutrient cycling. Others are important in seed dispersal or as scavengers. Ecologically, reptiles play critical roles in maintaining healthy ecosystems.

Threats and Conservation

Despite their long evolutionary history and adaptability, reptile populations face numerous significant threats, primarily driven by human activities. Unfortunately, many reptile species are facing significant threats.

Primary threats include:

• Habitat loss and fragmentation due to deforestation, urbanisation, and agricultural expansion.
• Pollution from industrial, agricultural, and plastic waste.
• Climate change disrupts behaviour, reproduction, and distribution through altered temperature and precipitation patterns.
• Overexploitation through illegal pet trade and unsustainable hunting.
• Invasive species that can outcompete or prey on native reptiles.

The current rapid decline serves as a stark reminder of the unprecedented scale and pace of modern environmental challenges. While reptiles have proven to be survivors, the intensity and multifaceted nature of threats like habitat destruction and climate change are pushing many species to the brink.

Why Conservation Matters

Conserving reptile populations and their habitats is essential. Their decline can have cascading effects throughout the food web and disrupt ecosystem balance. Furthermore, reptiles are an important part of Earth's biodiversity, representing millions of years of evolution and unique adaptations. Their presence enriches our natural world, and their loss diminishes the planet's biological heritage. Recognising their intrinsic value and the interconnectedness of all life underscores the importance of their protection. Understanding and appreciating these often-misunderstood animals is the first step towards ensuring their protection and recognizing their invaluable contribution to the planet's biodiversity.

Amphibians: Nature’s Dual-Life Wonders

What are the primary features of amphibians? What species group form the amphibians? What amphibian species can be found in the Sidmouth area?

Have you ever wondered about those fascinating creatures that seem to live a double life, equally at home on land and in water? Welcome to the incredible world of amphibians! The word "amphibian" itself comes from the Greek words "amphi" (meaning "both") and "bios" (meaning "life"), perfectly describing their unique existence. Unlike reptiles, mammals, or birds, amphibians undergo a remarkable transformation during their lives, adapting to both aquatic and terrestrial environments.

What Makes an Amphibian an Amphibian?

Amphibians are cold-blooded vertebrates that typically begin life in water and later move to land. While diverse in appearance, most amphibians share some key characteristics:

• Metamorphosis: This is perhaps their most defining trait. Most amphibians start their lives as aquatic larvae (think tadpoles!) breathing through gills. As they mature, they undergo an incredible metamorphosis, developing lungs and limbs that allow them to live on land.
• Moist Skin: Amphibians typically have smooth, permeable skin that needs to stay moist to help them breathe and absorb water and oxygen. This is why you often find them near water sources or in damp environments.
• Ectothermic (Cold-Blooded): Like reptiles, amphibians are ectothermic, meaning they rely on external sources to regulate their body temperature. They'll bask in the sun to warm up or seek shade to cool down.
• Vertebrates: Amphibians are vertebrates, meaning they have a backbone.

Who are the Amphibians?

The amphibian class is broadly divided into three main groups:

• Frogs and Toads (Anura): This is the largest and most well-known group. They are recognised by their powerful jumping legs, bulging eyes, and vocal calls. While often used interchangeably, "frogs" generally refer to smooth-skinned, more aquatic species, while "toads" are typically warty-skinned and more terrestrial. They belong to the order Anura, characterised by their tailless adult form and strong jumping legs.
• Salamanders and Newts (Caudata/Urodela): These elongated amphibians resemble lizards but lack scales. They have long tails and typically walk with a side-to-side motion. Many remain aquatic throughout their lives, while others are primarily terrestrial. They belong to the order Urodela or Caudata, possessing tails and typically four limbs of roughly equal size.
• Caecilians (Gymnophiona): The least known group, caecilians are legless, worm-like amphibians primarily found in tropical regions. They often live underground, making them quite elusive. They belong to the order Apoda or Gymnophiona.

Why are Amphibians Important?

Despite their small size, amphibians play BIG roles and are integral to the functioning of their ecosystems. They are often considered bioindicators—their health reflects the health of the ecosystem—because their permeable skin makes them particularly sensitive to pollution and habitat changes.

Amphibians contribute in several ways:

• Pest control: Frogs and toads eat tons of insects, helping to regulate insect populations.
• Food source: Many are prey for birds, fish, and mammals, forming a crucial link in food webs. Frogs are prey for grass snakes and herons, while toads and newts are prey for grass snakes.
• Medicine: Scientists study amphibian skin for new medical compounds. Some species, like the axolotl, exhibit remarkable regenerative abilities, offering potential insights for medical research.
• Nutrient cycling: Through their consumption and excretion, amphibians contribute to nutrient cycling within their habitats.

Amphibians in Britain and the Sid Valley

Amphibians are present in the Sid Valley. Waterways, ponds, and pools in the valley provide breeding sites for amphibians, where they lay their eggs. Brownfield sites can also be ideal habitats for them. Heathlands are noted as a vital habitat for the few UK species of amphibians.

In Britain, the two main groups of native amphibians are frogs/toads and newts. Specific species mentioned include Frogs, Toads, and Newts. The common frog and the common toad are native to Sidmouth. A frog population has colonised a new pond created in the Roncombe Valley. Frogs and Palmate newts are thriving and breeding well in the Lower Knapp Pond Reserve. The Lower Knapp Pond Reserve is listed as a specific habitat supporting amphibians. The natterjack toad is mentioned in the context of heathland habitats being important for amphibians generally and conservation efforts for this species are noted, though not specifically linked to Sidmouth heathland populations. Of the three native newt species, the great crested newt is now scarce and under conservation efforts. The palmate newt favours heathland habitats, making the smooth newt the most likely species to be found in garden ponds and locations like the Knapp nature pond in Sidmouth.

Interestingly, female frogs produce eggs starting in October and through the winter. When predators like grass snakes or herons eat frogs full of eggs, the eggs can swell in their stomach juices, potentially causing the predator to regurgitate the egg mass. These regurgitated masses, when dropped in a wet place, swell into clear jelly lumps (known as 'star jelly') which are effectively masses of frog spawn without fertilised ovules.

Threats and Conservation

Sadly, amphibians are among the most threatened animals on the planet, facing a multitude of threats. Globally, amphibians (frogs, salamanders, caecilians) may be the only major group currently at global risk, with one-third or more of species threatened.

Primary threats include:

• Habitat destruction and fragmentation: Due to deforestation and urbanisation eliminate and isolate amphibian populations.
• Pollution: Pesticides and chemical runoff contaminates their aquatic breeding sites and permeable skin, leading to health issues.
• Climate change: Disrupts their breeding cycles, migration patterns, and habitats through altered temperatures and precipitation. Rising temperatures can desynchronise breeding cycles, while changes in precipitation can lead to drying ponds or increased flooding. More frequent and intense extreme weather events further destabilise their fragile habitats.
• Invasive species: Can lead to competition for resources and the spread of deadly diseases.
• Disease: Such as the chytrid fungus (Batrachochytrium dendrobatidis, or Bd). This is a highly virulent pathogen causing chytridiomycosis, responsible for significant population declines and even extinctions worldwide. It disrupts the amphibian's skin function, essential for respiration and osmoregulation. This disease particularly impacts frogs. Salamanders on tropical mountains are particularly impacted by global conservation challenges and threats.

Various conservation initiatives are in place to address amphibian decline:

• Habitat restoration and protection: To ensure suitable breeding and terrestrial environments.
• Captive breeding programs: Aim to safeguard endangered species and provide individuals for reintroduction.
• Public education campaigns: Crucial for raising awareness about amphibian conservation needs.
• Scientific research: Focuses on understanding and mitigating threats like the chytrid fungus, including developing treatment strategies.

Get to Know Your Local Amphibians!

Keep an eye out for these amazing creatures in the area! Whether it's the distinctive croak of a frog on a summer evening or a glimpse of a newt in a pond, taking the time to observe amphibians can open up a whole new appreciation for the biodiversity around us.

Birds: Avian Jewels

What are the key features of birds? What is the status of birds in the Sidmouth area? What threats do birds face and what can be done about them?

Birds are truly captivating creatures that share our planet, found across every continent from icy polar regions to arid deserts, deep forests to our very own gardens. As vertebrates with a backbone, birds are uniquely defined by certain key characteristics: feathers, wings, and beaks. They are the only animals with feathers, which are essential for insulation, flight, and display. All birds also share the features of having beaks without teeth and the ability to lay eggs. While most can fly thanks to lightweight skeletons and strong chest muscles, some, like ostriches and penguins, have adapted to life on land or water.

With over 10,000 known species globally, birds exhibit an astonishing array of sizes, shapes, colours, and behaviours. Their remarkable ability to fly allows them to traverse vast distances and explore diverse habitats, while their intricate songs are used for communication, attracting mates, and defending territories. Whether it's the complex migrations of arctic terns or the dazzling courtship dances of peacocks, avian life is full of wonder.

Beyond their aesthetic appeal, birds play vital roles in ecosystems. They are significant pollinators, helping to transfer pollen between flowers, and seed dispersers, aiding plant propagation. Many also act as pest controllers by preying on insects and small animals, helping to maintain ecological balance. Scavenging birds contribute to nutrient cycling by consuming carrion. Their presence contributes to biodiversity and ecosystem resilience.

Closer to Home: Birds in the Sid Valley

Our region is blessed with a rich variety of birdlife. The Sid Valley and its various habitats support a diverse array of bird species. The valley's mild microclimate provides shelter and allows some insects, a crucial food source for birds, to remain active well past the summer peak. Diverse habitats within the valley, including woodlands, grasslands, hedgerows, heathlands, rivers, wetlands, coastal areas, urban spaces, and gardens, all contribute to this avian diversity. In spring, we welcome swallows and swifts back from their long journeys, while autumn brings the thrilling spectacle of starling murmurations. Throughout the year, birds offer a constant connection to the natural world around us.

Threats and Conservation Efforts

Sadly, bird populations both globally and in the Sid Valley face significant threats. Habitat loss, driven by factors like deforestation, agriculture, and urban development, is a major concern. Climate change also disrupts ecosystems, altering migration patterns and breeding cycles. Pollution, including pesticides, can directly harm birds or their food sources. Locally, issues like intensive agriculture, habitat fragmentation, changes in management practices (such as hedge removal), pollution, and predation contribute to declines. For instance, changes in farming have had a major impact on farmland birds, and river barriers like weirs can impact fish populations, which are food for birds like Kingfishers and Herons.

However, conservation efforts are underway to protect birds and their habitats. These include habitat preservation and restoration, as well as establishing protected areas like national parks and nature reserves. Locally, conservation efforts include managing habitats such as meadows, hedges, heathland, woodlands, verges, and ponds to promote biodiversity. Providing food and habitat in gardens through feeders, ponds, and wildflower patches is also important. Protected areas like the Sidmouth to Beer Coast SSSI, Fire Beacon Hill Local Nature Reserve, Delderfield Community Nature Reserve, and Sid Vale Association's nature reserves contribute to safeguarding important bird habitats.

Citizen science also plays a vital role in monitoring bird populations. The Big Garden Bird Watch is an annual project where Sidmouth citizen scientists participate, recording birds in their gardens to help organisations like the RSPB understand how species are faring. Surveying bird populations is crucial for conservation planning and assessing the effectiveness of conservation efforts. Local sightings from this survey are reported by the Sid Valley Biodiversity Group.

Why Conservation Matters

Conserving and protecting birds is essential for numerous reasons. Ecologically, they maintain healthy ecosystems through pollination, seed dispersal, and pest control. Culturally, birds enrich our lives through their beauty, songs, and symbolic significance. As stewards of the planet, we have an ethical responsibility to protect all forms of life. By supporting conservation efforts and appreciating the birds around us, we can ensure that future generations can continue to enjoy these wonderful creatures.

Specific Bird Species Mentioned:

• Buzzards are one of the birds of prey seen in the valley. Their numbers are very healthy in the Sid Valley. They can be seen soaring as strong thermals are created on clear days, especially in the wooded combes. Buzzards are seen regularly defending themselves from crows by whistling while riding thermals in tributary valleys like the Snod Brook and Roncombe Stream. They can be seen perched high on treetops when foliage is sparse. They are also seen in large numbers pacing up and down recently ploughed fields looking for worms, a behavior thought to mimic rain to bring worms to the surface.
• Sparrowhawks are among the birds of prey seen. They can be seen, especially when the sky is clear, soaring in sheltered valleys.
• Kestrels are among the birds of prey seen. They can be seen hovering motionless in Sidmouth Cemetery, looking for mice and voles to swoop on. Kestrels can also be predators drawn to fenced bird colonies on the coast.
• Peregrines are among the birds of prey seen.
• Merlins can be seen on Fire Beacon Hill. They can also be found on upland heathland.
• Nuthatches can be heard calling with a variety of repetitive calls in any of the mature woodlands in the valley. They are considered true woodland specialist species.
• Treecreepers will allow you to creep up on them, walking up trees with no effort. They are true woodland specialist species.
• Green Woodpeckers are heard "yaffling" as they peck for meadow ants amongst the long grass in Sidmouth Cemetery. They are seen/heard in The Byes, Margaret's Meadow, and Gilchrist Field. They feed from the ground and are resident in Britain all year round, visible even in winter. Green Woodpeckers are seen by day in The Knapp Nature Reserve. They feed on yellow meadow anthills.
• Greater Spotted Woodpeckers are seen/heard in The Byes, Margaret's Meadow, and Gilchrist Field. They use ancient trees for nesting.
• Blackcaps' sweet tuneful song can be heard in town, The Byes, Margaret's Meadow, and Gilchrist Field. They can often be found in woodland near Sidmouth Cemetery. Blackcaps are summer visitors to woodland. Their fruits provide important winter food.
• •Bullfinches can often be found in woodland near Sidmouth Cemetery. They are associated with wood pasture/veteran trees.
• Jays may be seen collecting and burying acorns, caching large amounts for winter.
• Tawny Owls can be heard all across the town as well as in The Byes, Margaret's Meadow, and from the Knapp. The classic 'twit-twooo' call is a duet between the female's 'kew-wick' and the male's response. They are active as the sun sets in the early evening in winter. Tawny Owls are much more common than Barn Owls. They prey on slugs and snails.
• Yellowhammers are resident birds of the heathland, found all year round, singing loudly in spring to attract mates. Their call sounds like 'a little bit of bread and no cheese', one of the easiest bird calls to distinguish. Males have bright yellow heads, females are duller. They are seen flocking in winter singing. Yellowhammers are found in shorter hedges. They are among species visiting heathland from surrounding farmland. Yellowhammers breed on the Fire Beacon Hill Local Nature Reserve. They are a Red Listed species.
• Dartford Warblers are rare species found on heathland due to the unique habitat. They have been pushed to near extinction from habitat loss but numbers have increased thanks to management. They may be seen flitting between gorse bushes, utilizing vegetation for cover. They nest in gorse bushes, which also provide invertebrate prey and protection from snow. Dartford Warblers are restricted to heathland only and are part of internationally important populations on heathlands. They breed on Fire Beacon Hill LNR. They are nationally scarce. A good tip for spotting them is to look out for the more conspicuous stonechat nearby.
• Stonechats are heathland dwellers, black-brown with a white throat and red-orange chest, size of a robin. They exhibit similar behavior to the Dartford Warbler. Their alarm call sounds like two stones being hit together, heard from gorse bushes. They are ground or low-bush nesting species seeking protection in gorse. They are conspicuous and can act as a sentry for Dartford Warblers.
• Wheatears can be heard on the heathland. A Wheatear photo is included in the Donkey Sanctuary surveys.
• Woodcocks can be heard on the heathland. They are ground or low-bush nesting species.
• Dunnocks can be heard on the heathland. Dense hedges and dry grass provide nesting cover for Dunnocks.
• Linnets can be heard on the heathland. They are found in shorter hedges. They are among species visiting heathland from surrounding farmland. The Linnet is a finch with a melodic song found on heathland, whose numbers are still decreasing. It is a resident, seen flocking and singing in winter. Linnets are a Red Listed species.
• Tree Pipits can be heard on the heathland. Pipits feed on invertebrates that multiply above long grass on places like Peak Hill.
• Meadow Pipits can be heard on the heathland. Pipits feed on invertebrates that multiply above long grass.
• Nightjars are nocturnal birds that start to arrive in late spring from Africa to breed. They are summer visitors mostly found in southern Britain, favoring heathland with surrounding conifer plantation. They hunt moths and beetles on the wing after sunset. Best time to see them is an hour after sunset. They can be heard making a loud churring sound or seen clapping wings in courtship. They nest on the ground during the day, easily camouflaged. They are of the highest conservation value in Britain and are globally threatened. Nightjar density tends to be greatest where there is some tree cover, along the interface between open heath and forestry. They are part of internationally important populations on heathlands. Nightjars are among the nocturnal heathland dwellers. Mutter's Moor supports a population of Nightjars. They are seen hawking for food at dusk and dawn on Fire Beacon Hill LNR.
• Skylarks are a Red Listed species recorded in the Donkey Sanctuary surveys.
• Kingfishers (Common Kingfisher) may be spotted darting up the River Sid, a flash of bright blue. You may see one or a pair perched on a branch ready to dive for fish or insects. Their numbers are decreasing and they are found predominantly in the south of Britain. Kingfishers are stocky, about the size of a robin. They are solitary and fiercely defend territory. They are most active at dawn and dusk. The River Sid provides an ideal habitat, especially where water is clean, oxygenated, and has small fish. Their presence is a testament to river health, though it is fragile. They are adept hunters, diving headfirst to spear prey. Their diet is mainly small fish like minnows and sticklebacks. They are cavity nesters, excavating burrows in steep earthen banks, where both parents feed chicks. They face habitat loss, pollution, and harsh winters. Conservation efforts are crucial.
• Dippers can be observed easily on the River Sid where it flows through The Byes and regularly nest beneath Lymebourne Bridge. The Dipper has a dark body and white chest; its name comes from its constant dipping motion. It can walk into and under water to search for food like shrimps and insect larvae. It usually prefers upland streams but in Devon can be seen in the lower reaches.
• Grey Wagtails can be observed easily on the River Sid where it flows through The Byes and regularly nest beneath Lymebourne Bridge. Grey Wagtails are mainly yellow, despite the name. They are among the birds feeding on invertebrates above long grass on places like Peak Hill. They are seen in The Byes, Margaret's Meadow, and Gilchrist Field.
• Pied Wagtails can be observed in The Byes, Margaret's Meadow, and Gilchrist Field. They are seen in town, like in Fore Street, scuttling around looking for insects. They have learned to live close to humans. They are black and white and easily recognised. Their long tail wags up and down. There are about half a million breeding pairs in Britain. They are widespread but come down from upland areas in winter for food and warmth. They can be seen in flocks around sewage works because of lots of flies and warmth. A flock of up to fifty often visits the Fortfield cricket pitch in winter. They are known as White Wagtails in Europe. They hide their nests in ivy, under roofs, or in crevices on old buildings. A pair nested in the thatch on the croquet shelter. They are a common sight on croquet lawns, spotting and eating insects near players. If food is plentiful, they have two broods per year. Young fledge quickly. They are among the birds feeding on invertebrates above long grass.
• Swallows dart through the air in town, The Byes, Margaret's Meadow, and Gilchrist Field. They are summer visitors that fly back to Africa for winter. They are seen across fields in large numbers feeding on insects low to the ground and will be seen perching on electricity lines. Swallows, swifts, and house martins nest in buildings. Swallows are seen by day in The Knapp Nature Reserve. They feed on invertebrates at sewage works.
• Moorhens feed on a variety of plants, invertebrates, and fish in the river.
• Crows feed on invertebrates at sewage works. Crows mob buzzards to try and push them out of their territory. Magpies (a type of crow) use tall trees in hedgerows as nest sites.
• Gulls use buildings as surrogate cliffs for nesting, especially in coastal cities. They are a common sight at refuse tips, scavenging on waste food.
• Lesser Black-backed Gulls were once summer visitors but some are now residents due to abundant food at landfill sites.
• Waders (Oystercatchers, Curlew) exploit invertebrate species in mudflats and salt marshes. Eighteen species of wading birds occur in substantial numbers on mudflats/estuaries, making them excellent for bird watching. Waders are particularly important in winter when food declines on land. They use these habitats as feeding stations or overwintering destinations.
• Turnstones live on Sidmouth beach during the winter, fleeing harsh northern winters.
• Blackbirds are seen in The Byes, Margaret's Meadow, and Gilchrist Field. They are seen in most gardens during the Big Garden Bird Watch, being second on the local list. Blackbirds are thrushes. Their numbers increase in suburban gardens during winter, with birds coming from the countryside for easier food. The UK blackbird population sees a dramatic increase in winter as over a million birds arrive from Scandinavia and the Baltic regions, many wintering in south England. These migratory birds are resilient and have slightly longer wings; males often have darker beaks than local birds. Slugs are eaten by blackbirds. Black-topped fruits are an important winter food source. Blackbirds use tall trees in hedgerows as songposts.
• Starlings are seen in The Byes, Margaret's Meadow, and Gilchrist Field. Starlings will turn up mob-handed at garden feeders. Arrival of migrant Starlings is a sign seasons are turning. The local population is swollen by millions of migrants from north eastern Europe in September. Nationally, there are about 1.8 million breeding pairs, half what there were thirty years ago. The winter flock on the cricket field includes local birds and numbers about 100. They help ground staff by feeding on pests like leather jackets in the turf and aerating it. Slugs are eaten by starlings.
• Blue Tits are among the variety of tits in The Byes, Margaret's Meadow, and Gilchrist Field. They are the most frequent local visitor to gardens during the Big Garden Bird Watch, seen in 14 of 15 gardens, usually in ones and twos, but sometimes in groups of five. Blue Tits are generalist species found in woodland, grassland, scrub, parks, and gardens.
• Goldfinches are among the variety of tits in The Byes, Margaret's Meadow, and Gilchrist Field. Dense hedges and dry grass provide nesting cover for Goldfinches. Their stunning red and yellow feathers were seen in 6 gardens, moving in small flocks in winter; 14 landed in one garden, making them number 3 on the local list. Goldfinches are increasingly visiting gardens, which is thought to be helping their numbers increase steadily. They are plentiful in the Sid Valley in the colder months due to the shelter it offers.
• House Martins dart through the air in town, The Byes, Margaret's Meadow, and Gilchrist Field. They are summer visitors that fly back to Africa for winter. They nest in buildings, typically under eaves, often on the fringes of town and villages. They stay around until autumn, seen darting around later than other swallows/martins.
• Sparrows will turn up mob-handed at garden feeders. Tree Sparrows are an uncommon species associated with hedges. Loss of available nest sites in hedgerows is thought to be one reason for the 95 percent reduction in Tree Sparrow abundance.
• Chaffinches hide away in hedgerows, males making a considerable sound. Chaffinches are generalist species found in woodland, grassland, scrub, parks, and gardens.
• Robins are the size of stonechats. Robins are generalist species [Not explicitly stated they are generalists, but implied by being common garden birds].
• Greenfinches are increasingly rare but flit through cypress trees in Sidmouth Cemetery feeding on tiny insects.
• Rooks have a rookery in trees off Lymebourne Park and another near the entrance to Sidbury Manor. Their traditional 'kaah' call is heard.
• Song Thrushes are seen/heard in The Byes, Margaret's Meadow, and Gilchrist Field. Slugs are eaten by song thrushes. Black-topped fruits are an important winter food source. Song Thrushes use tall trees in hedgerows as songposts.
• Mistle Thrushes are seen/heard in The Byes, Margaret's Meadow, and Gilchrist Field.