Showing posts with label Bullfinch. Show all posts
Showing posts with label Bullfinch. Show all posts

Saturday, 1 March 2014

Fresh year, new months, same old battle.

For a meteorological metaphor, simply ask the heron.


Each winter presents a challenge for wildlife, and although we are yet to experience a consistent period of frost, or the disruptive influence of ice and snow, the mix of wet and wild weather has brought its own problems for the local fauna and flora.
 With the days naturally shorter, there is far less time for species to take on the nutrients needed to protect them from winter's inclement mood.  Food is scarcer than during the spring and summer months, so the negative influence of wind and rain during daylight hours is more than an inconvenience: it is an obstacle between wildlife and survival.


  Severe rain and gale force winds will make us bolt the doors and turn up the fire, but wild animals need nutrients to survive, and prioritise food for energy not enjoyment. It is difficult to know how a goldcrest, weighing no more than a 20 pence piece, can survive any breeze at all, let alone the fierce winds of the past few months. A day of insufficient food means their bodies are ill-equipped to cope with the wintry conditions, and greatly reduces their chance of survival. In winds that have blown down trees, and floods that have swept through houses, each day is about finding enough food to survive until tomorrow.
   It's a little difficult to tell from the photograph below, but this bald bird is a great tit. Such birds are known to moult naturally at the end of the summer, as the old feathers fall from their follicles to be replaced by new, which will help keep them warm during the winter months. 
Great tit (Parus major)
  Stress and a poor diet can also explain why a bird is losing its feathers. Given that this photo was taken in January, it is possible that a lack of nutrition is the cause of its baldness, or the stress associated with the competition for food. It could also be that the bird is sick or has mites, both of which will affect its ability to satisfy its increased need for food.
Jackdaw (Corvus monedula)
 There are significant benefits for wildlife living close to the Sanctuary, as demonstrated by these jackdaws on Baboon Island. Any fruit or vegetables discarded by the well fed residents is gratefully scavenged by the surrounding wildlife, be it birds, mammals or insects. This ensures a regular source of  nutrition throughout the year, and a bonus come winter. When this additional source of food is combined with the natural resources that have maintained these native species for generations, it is little wonder that the sanctuary is constantly alive with the sound of birdsong. 
Starlings (Sturnus vulgaris) congregate above Baboon Island
  With open fields, closed woods, and various waterways in and around  the  Sanctuary,  the  area  is  busy  with a variety of different  species all searching for food.

 This male blackbird (Turdus merula) has chosen to feast on the plentiful red berries of the rowan tree (Sorbus aucuparia). Later, the seeds will be dispersed in the bird's droppings, allowing the rowan tree to expand its presence over a wide  area, thus providing a new generation of food for the birds. Seeds and buds are an important food source,  as indicated by this bullfinch (Pyrrhula pyrrhula) [pictured below], ardently chewing at the barely emerging bud.  
  Below, a siskin (Carduelis spinus) can be seen feeding from a common alder tree (Alnus glutinosa), biting into the cone in an attempt to acquire the small seeds within. The alder seeds are dispersed by the wind from around October, so February hunger means biting deep for those not naturally dislodged. From the picture on the right, it appears the siskin has been successful on this occasion, although it doesn't appear to be much of a return for its efforts.

Siskin (Carduelis spinus)

Treecreeper (Certhia familiaris) [above and below]
  Staying in the trees, the treecreepers spend their daylight hours searching for insects and spiders hidden in the mosses and bark. There are many treecreepers living in and around the Sanctuary's woods, and are especially prevalent closer to the riverside, where they probe the dead wood of fallen trees. The abundance of insect eating birds points to the Sanctuary being a perfect environment for a variety of invertebrate. The treecreeper below has claimed a protein rich grub from the tree and holds it, cigar-like, in an almost celebratory pose. Such morsels are essential to the nutrition - energy balance, with birds needing maximum nutrition from as little energy as possible. 
Wren (Troglodytes troglodytes)


  The wren is another bird that feeds off insects, invertebrate and spiders, and at the Sanctuary is usually found in close proximity to the treecreeper, sometimes sharing the bounty of a decaying tree, strewn across the river. The Sanctuary's mix of woodland and water offers a perfect environment for this little bird. While it remains a common species, its overall population can be negatively affected during difficult winters. The constant rain and violent winds of recent months must have been quite a trial for a bird so small.
Nuthatch (Sitta europaea)
 The previously
admired nuthatch is another successful species in this part of the world, and it isn't any wonder. Despite being small, it has a strong, stocky frame, and a bill designed to crack through nuts. Part of its success is doubtlessly down to the variety in its diet, for as well as eating invertebrate, it will feed off nuts and seeds. Nearly always found in trees, it can easily be lured to garden feeders, especially when sunflower seeds are on offer.
  Another bird that can be tempted by an appropriately stocked feeder is the great spotted woodpecker (Dendrocopos major). Another species frequently found in trees, this particular woodpecker was drumming on this telephone pole. In summer, such behaviour could be a sign of searching for an available mate, although in January it is much more likely to be looking for food. Woodpeckers peck the bark from trees and dead logs to gain access to insects and grubs, something it is less likely to achieve from this pole, which is coated to prevent it from rotting.
Great spotted woodpecker (Dendrocopos major) searching the dead bark for invertebrate last October.

  One aspect of the rain is that it draws worms closer to the surface, and makes the local fields rich pickings for numerous species of birds and mammals. With this in mind, it appears that for some species the winter might not have been too bad, at all. 
Blackbird (turdus merula)
   
Blackbird (Turdus merula) searching a field with a mistle thrush (Turdus viscivorus) in close attendance (and below).
  It is the unrelenting nature of the rain that has made the winter seem  unending, yet the redwing have returned for their winter sojourn. Spending their summers in Scandinavia, some redwing will journey further south into mainland Europe, and use the UK as nothing more than a stopover, while others will remain here for the season. The milder temperatures, and wet, soft fields must appear particularly inviting this year, with flocks of redwing sighted across local fields. The decline in redwing populations means it continues to be a red status species, so it is encouraging to see such numbers at the Sanctuary.

Redwing (Turdus iliacus)

  Another major beneficiary of the wet weather is the grey heron. A regular fisher of the local rivers, lakes and ponds, the milder weather has maintained easy access to the ice-free waters.
 Grey heron (Ardea cinerea)

  In moments when the rain finally eases, and the wind dies to a mild breeze, it may seem that it hasn't been a bad winter, at all. At least for some. The riverside birds seem to take it all in their stride.
Grey wagtail (Motacilla cinerea)

Dipper (Cinclus cinclus) 
  There might not be anything new in this winter collection of Sanctuary wildlife, but it is nice to see the regulars coping with the  somewhat unseasonal conditions. And while I have managed to snap those that can be seen frequently, they are but a fraction of those that have gone undetected, in spite of their observation of me. As can be seen from the picture below.


  The usual suspects are also out and about. 
Long tailed tit (Aegithalos caudatus)
Blue tit (Cyanistes caeruleus)

House sparrow (Passer domesticus) 
Grey Squirrel (Sciurus carolinensis)
  So has the winter been so bad? I suppose it depends on who or what you are, and what you depend on for survival. Many have not made it this far, but for those who have there is a promise of spring in the air. The sunlit hours are increasing daily, the early crocuses have flowered, and the buds of the willow are emerging. While it brings excitement and hope for the months ahead, there remains the prospect that the worst of winter is still ahead of us. Whichever, nature will find its way of surviving.






Sunday, 10 March 2013

And the year began...with something a foot.

January / February 2013

  The early days of the year had few redeeming features. The rainfall theme of 2012 look set to continue until the temperatures finally dipped, and the snow arrived by the blizzard. The more hardier Sanctuary residents, such as the chimpanzees, ventured out into their freshly whitened surroundings (prompting international fame for Nakima), but most were content to remain indoors, watching the cold from their heated quarters. Only Julie, the snow monkey (Japanese macaque), was in her natural environment, yet she too was attracted to the indoor warmth, like her species is drawn to the natural hot-springs of Nagano, Japan.
  By the end of January, the recent snow had largely melted but the air remained cold. Frequent showers of rain and hail drove hard from a slate grey sky. Trodden grass was mulched into mud. Rivers were high and raucous. Wildlife was sparse, preferring to shelter from the elements, only surfacing to quench their most essential needs. The treecreeper was one such venturer, scouring the tree trunks for spiders and insects, its curved, slender bill breaching the natural cracks and crevices in the bark.

Treecreeper (Certhia familiaris)

                                    

  As I watched, I was drawn to the small bird's motion, spiralling up the tree with the natural ease of our horizontal stroll. Even the wings, casually folded back into its streamlined body, seemed to emphasise the ease with which it engaged this vertical ascent, mimicking - almost mocking - the way our hands clasp behind our backs as we embark on a leisurely constitutional.
  When admiring birds, I suppose it is the wings to which we are usually drawn. After all, they are the biological motors of our envy, wonder, and much sought action: flight. They are largely the reason for the birds success on this planet, providing them with a pocket of co-existence just above our heads. But it is also on the wing that the bird looks more comfortable, providing a grace, stealth and agility it often lacks on the ground. In comparison, the feet often appear weak and spindly, as they awkwardly transport the bird a hop or two at a time. They offer no recourse for escape, just a cumbersome bipod for when they are most vulnerable.
  Yet the feet of this remarkable treecreeper reveals a different story, as they speedily propel this bird up the tree. And so I look closer. In common with most UK songbirds, the treecreepers' feet are anisodactyl. This means there are four digits, with three toes facing front and the fourth facing back. Each toe has a curved keratin claw, which the treecreeper uses to grip onto the wood and moss. In the above photographs, it can also be seen using its tail as a prop. 

  Another proficient climber is the nuthatch. Seen here gripping onto a telephone pole with similarly long, hooked claws, it can often be seen scurrying up and down the sanctuary's surrounding trees. Verticality holds no fear for this bird, as its grip on wood is sufficiently strong to descend at quite a speed. It will also make use of the sunflower seeds offered from the bird tables of surrounding gardens, particularly in winter, when invertebrate can be harder to find.

Nuthatch (Sitta europaea)


  The size of foot and claw vary from species to species, as demonstrated by this female house sparrow, whose feet appear much smaller than those of the treecreeper and nuthatch. Despite also being anisodactyl, three toes forward one back, their feet are better suited for perching. 

Female house sparrow (Passer domesticus)

  Male house sparrow (Passer domesticus)

Coal tit (Periparus ater)


  The toes of the anisodactyl foot can move independently of each other. Such flexibility maximises the ability to grip onto different objects and surfaces, something which is essential for their access to food and cover from predators. When perching, the back toe comes round to meet the forward facing three. Although they do not possess the dexterity of the human hand, the action is reminiscent of opposable thumbs, and the grip a gymnast uses to secure a hold on the parallel bars.

Great tit (Parus major)

 


Song thrush (Turdus philomelos)

                                       

  As a bird sits, an ankle tendon automatically locks the anisodactyl toes into position around the perch. This allows them to feel secure, particularly when sleeping at height. When the bird stands, the tendon unlocks the toes, releasing the bird to move freely on or from its chosen perch.

Female house sparrow (Passer domesticus)


   This blue tit perfectly demonstrates the feet's strength of grip, and the flexibility it affords the small bird. But it also shows its delicacy of touch.

Blue tit (Cyanistes caeruleus)


  Appreciating the fragility of dead leaves, the bird is clearly applying a measured amount of pressure, ensuring it does not pierce or destroy its chosen perch.


 Jackdaw (Corvus mendula)

                                  

  Perching birds are typically known as "passerines" as they, together with over 5,000 species, are included in the scientific classification order, "Passeriformes". Observing a perching bird, it can appear that much of its flexibility comes from a knee that bends forward in the opposite direction to that of the human joint. But where we might expect the knee to be in relation to our bodies, is actually the passerines' ankle. The knee is further up the leg, largely unseen, hidden by feathers.  


  Those independent digits are also useful to secure food in position when eating. In this instance the food appears to be bread, but the action becomes that much more relevant when a bird needs to tear flesh with its bill.



  The flesh tearing action is a particular feature of birds of prey, whose feet have evolved into talons. This evolutionary trait has allowed them to specialise in hunting for small mammals and birds. During the winter, the common buzzard remains a regular sight at the sanctuary, scouring the surrounding countryside with its keen eye.

Common buzzard (Buteo buteo)

                              

  Like the buzzard, the grey heron likes to fulfil its carnivorous side, and are often seen fishing along the Sanctuary's nearby rivers, which are well stocked with fish.

likely id: Rainbow trout (Oncorhynchus mykiss) taken September 2012


  Unlike the raptors, the heron does not use its feet to inflict a killing blow, but will use them to entice prey by creating vibrations in the water. This is known as Foot Stirring, and is covered at www.heronconservation in a paper called "The terminology of courtship, nesting, feeding and maintenance in herons" by James A Kushlan.
  The heron will wait patiently in the river shallows, using its bill to spear passing fish that it will then swallow whole. The herons' anisodactyl toes are slender and long, and unlike most birds, whose feet fold in when flying, the herons' feet trail behind them in flight, perhaps creating a drag that is more than made up by an impressive wingspan.

Grey Heron (Ardea cinerea)






 Another fish-eater on the local rivers is the goosander. Its webbed feet, the unseen motor, manoeuvres the bird along the water in search of prey. When discovered, it submerges its head to snatch the unsuspecting fish with its razor bill. The photos below show how the bright orange feet help propel the goosander from the water to the air.

Male goosander (Mergus merganser)







Female goosander (Mergus merganser)


 
  As ever, the mallard ducks continue their life on the freshwater surrounding Baboon Island, but the lone moorhen appears to have found a mate. It is nice to consider the prospect of further moorhens at the sanctuary this spring.
  Every year, there is a fight to survive the challenges winter brings. There is a prevalence of the more common birds, whose higher population makes them better prepared to take the mortality strain compared to those of lesser numbers. There are plenty of robins, tits, chaffinches, sparrows, blackbirds, and corvids, as well as a healthy spattering of wrens and dunnocks. But it is always nice to see a bird that can be a little more difficult to spot, even in summer, such as the bullfinch.

Male bullfinch (Pyrrhula pyrrhula)

                    

  With spring threatening, the wildlife is preparing for the start of a new cycle. Their attention is turning to nesting, mates, and a new generation. Daffodils and early crocus have joined the flowering gorse bushes in colouring the landscape. They are a hopeful sign against the whim of nature. 

Early crocus (Crocus tommasinianus)

Male and female blackbird (Turdus merula)