Species of the month
BROUGHT TO YOU BY RIVER SIX
Robin - December 2020
Christmas is not going to be the same this year, but some things remain the same, like our constant friend thoughout the seasons, the nation's favourite bird, the iconic Robin. At around 14cm in length and weighing just 18g, these birds are brown with white bellies and red breasts, the males and females are practically identical. The Robin is a member of the thrush family and iso is also a relative of other garden favourites, the Blackbird and the sadly declining Nightingale. Robins can be seen in parks, gardens, scrubland and woodland throughout the year but at this time of year become more visible and audible. As soon as Robin chicks come of age, it is every Robin for themselves. Males and females defend teritories outside mating season, unusually with both performing the autumn and winter song.
Also known as Robin Redbreast, it may look beautiful but can be a real bully! The Robin will fight with incredible ferocity to defend its territory and may fight another Robin to the death, especially if that involves a well stocked bird feeder! The Robin's diet is varied and is likely to change throughout the year depending on availability, food stuff includes insects, spiders, worms, seeds, fruit and berries. When our island was a forest the Robin would have likely followed the wild boar around and fed from the unearthed worms in the boars' wake, this behaviour has been adapted to them becoming our ‘garden friend.’ They often perch nearby waiting for gardeners to disturb the soil and will swoop in for the easy meal. Sadly the recovery of ringed birds has indicated that the most common cause of premature death in Robins is being killed by domesticated cats.
Robins have been associated with Christmas since Victorian times. It is thought that their appearance on Christmas cards was inspired by Victorian postmen who were known as Robin Red Breasts due to their red waistcoats. The Victorians were responsible for some fantastic wildlife discoveries and exploration, but also of some awful wildlife crimes like when Robin skins became popular as decorative features of ladies’ hats! Each robin has a unique breast pattern, and can (with difficulty) be recognised individually. And as for the colour, there are a number of origin myths explaining how the Robin got its red breast. Some legends say that the Robin was entirely brown, but was stained by the blood of Jesus as he was dying on the cross. The robin is said to have picked out the thorns of his crown, or to have sung a comforting tune in Jesus’ final moments. Other tales describe how the robin brought food to the souls in purgatory and its breast was scorched by the flames.
Fieldfare - November 2020
Along with their more easily identifiable Redwing cousins, Fieldfares have arrived in Otley! I often feel a little sad noticing all our summer migrants have left, it has been a couple of months now but Fieldfares arriving along with our other winter visitors always put a smile on my face. Their bellies are white, their breasts and flanks are tinted orange and are heavily speckled. They can be found living in flocks which can be quite large, often mixed with Redwings, in a variety of habitats including hedgerows, woodland, farmland and gardens around Otley.
Each year, thousands of fieldfares leave Scandinavia and even Russia to spend the winter in the comparatively mild UK, so remember that when you feel it’s too cold to go for a walk! Fieldfares stand upright, almost proud and on foot they move forward with purposeful hops. The name fieldfare is derived from the Anglo-Saxon word ‘feldware’ which meant ‘traveller of the fields,’ probably from their constantly moving, foraging habits. Which is the other reason they come to us, our hedgerows and woodlands are brimming with fruit, their diet features large amounts of these berries and fallen fruits; hawthorn, holly, juniper and yew are some of their favourites. Like our year round Mistle thrushes, Fieldfares will aggressively defend a food source, such as a fallen fruit, chasing away any other birds that get too close.
Towards dusk, Fieldfares congregate, often with Redwings to roost together and, if a tall hedge or tree is selected, they all face the same direction when they sleep. The fieldfare is a bird that has been historically hunted for food. There is evidence from AD 150 that the Romans enjoyed roasted Fieldfare and, in Germany, they were officially hunted until the early 20th century. One record shows that in the 17th century, approximately 600,000 fieldfares were caught in one season by Prussian trappers. Thankfully those sorts of numbers are no longer taken, but in some continental countries the birds may still be trapped or hunted between September and February.
Fieldfares are a very vocal species, as they take off they make a ‘chook-chook’ call, this could be to keep in contact with their flock, as they are such a social species. By March most of our Fieldfares will have crossed the North Sea back to their nesting grounds, although some hang on until as late as May! Unlike other thrushes Fieldfares nest in small colonies and build cup-shaped nests from grass, moss and twigs and lined with mud, usually in trees. Fieldfares have been spotted dive-bombing predators who try and approach their nest and firing poo at them to keep them away.
Photo by Pixabay
In striking contrast to Redwings and other thrushes, Fieldfares have a habit of rising vertically into the air, displaying their grey head and rump. By spring, the dark parts of a fieldfare’s beak have turned yellow and the grey plumage is now pristine. In 2004, a study revealed that Fieldfares have a very clever breeding strategy to outwit predators. Whether or not they nest in their usual colony is decided by rodent numbers, in years where rodent populations plummet, Ravens and Stoats instead target Fieldfares – especially nesting birds and their eggs. So nesting in a colony would make far too easy a target, so instead Fieldfares tend not to nest in colonies in those years, instead nesting in isolation. When nesting solitarily they are much less vocal and uncharacteristically don't sound alarm calls when Stoats or Ravens are in the vicinity.
Photo by Pixabay
ATLANTIC SALMON - October 2020
At this time of year Atlantic salmon join our more familiar brown trout in the high jump contest taking place up our fast-flowing weir to spawn up stream. And just like athletes the fish can often be spotted warming up below their obstacle waiting for the optimum moment to make the leap. The salmon are capable of leaping 4 times their own body length, which when experienced brings to mind a time when this valley was a true wilderness and the salmon weren’t leaping a weir but a waterfall to avoid the clutches of the native bears. Without the bears, the salmon still have many predators to avoid including otters, herons and the most formidable, fisherman.
The natural breeding range of the Atlantic salmon is massive from rivers along the east coast of North America to Europe, including our own River Wharfe. Unlike it’s relative the smaller Pacific salmon who make similar journeys up the rivers they were born in, return to the sea to repeat the journey another year, most of our larger Atlantic salmon do not survive the journey inland. Salmon are such popular fish, each part of their life cycle has been named. After hatching in the spring, they are called alevins, they then remain in the relative safety of the gravel for around a month. After which they emerge as fry, These fry soon become parr, and live in our freshwater rivers, feeding on invertebrates. When they reach 3 or 4 years old, they become smolts and head to sea.
During their smolt stage, Atlantic salmon undergo a fantastic change from a freshwater species to a saltwater species, you may ask why do salmon go to sea? It is a perilous journey but the bite-size prey they have hunted in the rivers are no longer enough, to continue to grow they must head to the ocean. The energy content and abundance of food in the ocean is much higher than in freshwater, so fish are able to grow very big, very quickly on their diet of krill, sand eels and herring. This is important because larger fish are less likely to be eaten and the females will ultimately produce more eggs. As well as plenty of more prey however the oceans holds plenty more predators for the salmon, including larger predatory fish like Atlantic halibut, Atlantic bluefin tuna and sharks, seabirds such as the Northern gannett, seals and toothed whales.
The next leg of the great journey brings the Atlantic salmon back to our River Wharfe, as incredibly they return to the river in which they were born to spawn. Only this time the adult salmon must swim upstream, against the flow of the river! During this change from seawater to the freshwater of the river, Atlantic salmon lose all their teeth and grow new ones. Very few other fish can survive in such wide ranges of salinity, and would die if they moved between salt and fresh water the way that salmon do. Scientists believe that salmon navigate their way back to the river in which they were born by using the Earth’s magnetic field like a compass. Years previously, these impressive fish were just tiny eggs buried in the gravel of the riverbed, gently placed there by their mother gently swooshing her tail.
CRANEFLY - September 2020
Often called a Daddy Long Legs, along with the completely unrelated Harvestmen who are arachnids! There are actually a number of different gangly craneflies on the wing throughout the year but this month sees the mass hatching of probably our most common and larger species, Tipula paulosa but will also answer to Cranefly or Daddy Long Legs. The easiest way to see these guys is to sit and wait by a porch light, they usually coming crashing into one at some point, alternatively go for a walk in long damp grass and one or two are almost guaranteed to stumble up into the air, looking like they are struggling to get airborne with all those limbs.
Like all flies they start life in a larval stage, to find their dull grey maggots, known as ‘leatherjackets,’ check out short grass or mossy areas close to the edges of steams or ponds. They rarely eat after pupating into the familiar dangly adult, so at their leatherjacket stage they have to gorge themselves, they live just underneath the surface of the soil feeding on detritus, roots and plant material they drag down. After many months of eating they pupate in the soil before emerging as the not so elegant long legged Cranefly, leaving a crunchy black/brown cask poking halfway out of the soil.
The female Cranefly is larger than the male but with shorter wings than her abdomen. Whilst males are generally smaller with relatively longer wings. Females produce between 200 and 300 eggs and emerge as an adult insect full of eggs, ready to meet a male. Because they are burdened with all these eggs, females are not able to fly very far, mating must take place as soon as possible, so the eggs can be laid. 14 days later the larvae (leatherjackets) hatch and start feeding immediately. The leatherjackets spend the winter in the soil and can continue to be active in temperatures as low as 5°C.
The larvae of the Cranefly (leatherjackets) play an important role in the food chain of many other animals. They have a long list of predators, including mammals such as shrews, hedgehogs and moles. Many birds, including blackbirds, starlings and woodpeckers will also hunt leatherjackets. As adults they are still tempting targets for birds, which might explain why their thin long legs are so weakly attached to their abdomen and can easily break off to escape an attack. There are a lot of myths around craneflies; they’re sometimes said to be one of the most venomous insects, but this is not true, they are actually completely harmless. They don't have any poison! And although they superficially look like mosquitos, they do not bite
ROE DEER - August 2020
The Roe is one of our truly native deer, the other being the Red deer. Records of them date to before the Mesolithic period (6000 to 10000 years BC). We are fortunate to have a breeding population living on Otley Chevin and now is as good a time as any to try and spot one, as their rut (or breeding season) is in full swing. Bucks have become aggressive and maintain exclusive territories around one or more does. Fights between bucks can result in serious injury or even death with the winner taking over the loser’s territory or attendant doe. Courtship involves chasing between the buck and doe for some time until the doe is ready to mate.
Roe deer are dainty creatures with large black eyes, nose and big ears. They have a body size a little smaller than a Labrador, but with long graceful legs. The males (bucks) sport small antlers, which have three points when fully grown. Roe deer vary in colour throughout the year, being most distinguishable now and throughout the summer when their coats are rusty red. In winter, their coats turn a dull, slate grey colour. Both sexes have a prominent white rump and appear to have no tail, as it is actually very small in comparison to other deer species.
Roe’s use well-worn paths across their range, leaving small hoof prints about 4 cm long in soft ground and small piles of faeces, the scat will usually be cylindrical with a dimple one end and a nipple on the other. The Buck will mark his territory by scraping at trees and laying scent from the glands in between their toes, whilst also frequently urinating to mark their territory. Roe deer are generally found in open mixed, coniferous or purely deciduous woodland, particularly at edges between woodland and open habitats, you can see why the Chevin Forest Park is ideal territory for them!
The Roe deer’s diet is varied and includes buds and leaves of deciduous trees and shrubs, bramble, rose, ivy, herbs, conifers, ferns, heather and grasses. They eat buds and leaves from trees and shrubs, as well as ferns, grasses and heathers. One of their favourite foods is plentiful up on the Chevin, Beech nuts. Unfortunately, the eating habits of deer can sometimes have a negative impact on woodland ecosystems. By feeding on young trees, deer can prevent the natural growth of new woodland. Large numbers of deer can also eat plants that other wildlife, such as birds and insects, depend on for food and shelter. Historically, predators such as wolves and lynx would have kept deer numbers in check, limiting these impacts. Whilst the adults have no natural predators left; the young are occasionally taken by foxes.
Incredibly the doe has evolved a delayed implantation strategy, the roe deer is in fact the only hoofed animal in which delayed implantation occurs, so that the young are not born during the harsh winter months. Once fertilised by the buck, the doe keeps the egg in her overies until late December and then implant it to the womb and 5 months later the kids (usually two or three) are born in May/June, a time of plenty in terms of food. Young Roe deer make a high-pitched whistle to attract their mothers when they become lost.
BUZZARD - July 2020
Most of this year’s young will be fledging now, so there will be more Buzzards around Otley now than any other time of the year. The young will eventually be pushed out of their parent’s territory and have to find their own. It is thought that the buzzard is now our commonest bird of prey, pushing the kestrel into second place.
Buzzards are monogamous and once paired will mate for life. A male attracts a mate, or impresses his existing one by performing spectacular aerial displays often called ‘roller coasters’.
The bird flies high in the sky, then turns and plunges down, twisting and turning in a spiral, to rise again immediately and repeat the display. From March to May, a breeding pair construct their nest in a big tree on a branch or fork, the nest is a bulky platform made of sticks and decorating it with fresh green foliage, where the female lays two to four eggs.
Buzzards will eat a wide range of food, principally small mammals but also birds, reptiles, amphibians and earthworms! Whilst they are impressive high fliers, their favourite hunting technique is to perch on bench posts, dead tree, rocks etc and scanning surroundings, then sweeping directly onto its located prey. In fact they spend so much time quietly sitting around, if you spot a large bird perched on a telegraph or fence posts it is very likely to be a Buzzard.
Whilst the Buzzard is our most common bird of prey now, this hasn’t always been the case. Persecution by gamekeepers and the use of pesticides meant the species had disappeared from most of the country by the mid-20th century. In Scotland, the buzzard is sometimes called the ‘tourist eagle’ due to visitors mistaking it for the larger bird. Before you see them, you are likely to first hear their iconic call, often described as a cat-like ‘’meow” or “kee-yaaa.” Their call is so impressive is it often played on TV when filming an eagle, as the eagle call is much more subtle.
COMMON FROG - June 2020
Our most well known amphibian, the Common Frog is a regular visitor to gardens across Otley. In fact our garden ponds are really important habitats for our frogs, especially when it comes to breeding time. In spring males arrive first and will perch themselves somewhere near the pond and croak to attract females, which are often significantly larger than the males. When a connection is made, the male will then often ‘piggyback' the rest of the way to the pond on a female. The frogspawn is laid in shallow, still water which is why garden ponds are perfect.
Frogspawn is fascinating, there can be up to 2000 small black eggs, each surrounded by a 1 cm jelly capsule. The raft of spawn is over 99% water but loses heat to the surrounding water very slowly, maintaining a nice warm temperature inside for the egg. Each of the many eggs are also permeable, so everyone gets their share of oxygen from the surrounding water. As the tadpoles grow they become faintly speckled with gold and brown, this is how you can tell them apart from the Common Toad tadpoles which remain all black. At about 16 weeks old, the tadpoles gradually change into froglets by first growing back legs, then front legs and finally by ‘absorbing’ their tails. This process is known as metamorphosis.
After populating your pond with tadpoles, adult frogs become our allies, if allowed to do so they can clear out those pesky slugs and snails from your garden! As adults, Common Frogs have smooth skin that varies massively in colour from grey, olive green and yellow to brown, amazingly they are able to lighten or darken their skin to camouflage with their surrounding environment and improve their chance of survival. Adult Frogs can live up to 10 years old, if they don’t get eaten first by their many predators; including grey herons, foxes, otters, birds of prey and domestic cats.
In winter frogs hibernate in pond mud, under log piles or in compost heaps. This choice of sleeping on the land or under the water is possible because the oxygen uptake through the skin is enough to sustain the frogs during hibernation. They will take advantage of milder patches of weather throughout winter, by waking up to forage. At around 3 years old the adults are ready to make more tadpoles, as soon as they wake up in early spring, they will head to a pond to breed and the cycle begins again. At this time of year it is the tiny ‘adult’ frogs you should look out for, leaving the pond for the first time to try out their land legs!