P is for Pied Wagtail

PIED WAGTAIL (MOTACILLA ALBA)

 The dainty pied wagtail is a common and regularly seen across the country. This little bird brings a sprightly charm to our city streets. 

With their pied plumage and long tail, pied wagtails look a bit like a miniature magpie  Pica pica (some people unfamiliar with birds believe they are baby magpies). Male pied wagtails are truly black and white, whilst females have a grey wing mantle. As their name suggests, they almost constantly wag their long tail up and down. Nobody knows exactly why they perform this eccentric behaviour, but hypotheses include signalling to other wagtails, signalling their alertness to predators, providing camouflage against running water (which most wagtails are associated with), as a still silhouette would stand out against a moving background, or to startle their insect prey out of hiding¹.  People likened this streamside bobbing to a maid scrubbing washing in the river, giving it the local names “Polly dishwasher” and similar².

Pied wagtails get around by walking with bursts of zippy, skittering dashes, so fast their legs are a blur to our eyes. Their repetitive call is a spontaneous “chi-ssick” sounded from the ground or in bounding flight. Males also have a rambling song, which is rarely heard.

Of all our wagtails species*, the pied wagtail is the least associated with water. Though they are often found in wet places, they also prefer wide, open areas where they can easily pick out their prey on the ground and spot potential predators. Paved and tarmacked surfaces are ideal, and pied wagtails have taken well to our streets and car parks. Our cars provide an added bonus, as they will pick the squashed insects off number plates. 

Though they are mainly insectivores, pied wagtails are always grateful for a handout of crumbs. The only time a wagtail was encouraged into our garden was last year’s snowy winter when it fed on the crumbs of our fat balls, and in Falmouth, Cornwall there is a male wagtail missing a foot, who seems to make his living and feed his chicks on Cornish pasty crumbs.

After a frantic day feeding on the ground, wagtails gather to roost in a tree or other perch. These mass-roostings are a magical spectacle, with trees festooned with feathery bundles like a Christmas tree (in fact they often use town Christmas trees). They gather on the ground, roofs and nearby perches before circling into the roost together with a cacophony of excited chattering before they all settle down. These roosts may number hundreds or thousands of wagtails. The largest recorded, in a Kentish reedbed, held 5000 birds³!
Though they don’t physically huddle, these gatherings may create a warmer microclimate to help the small birds survive in cold nights. They often choose to roost under the warm glow of a street light or sometimes in greenhouses on hot water pipes³.  

As with many resident British Birds, numbers of pied wagtails are swelled by migrants from the North in the winter months. During this season when food is scarce, adult male pied wagtails are territorial, whilst females and subordinate males forage in flocks. Though sometimes the males tolerate another ‘satellite’ wagtail in their territory who helps to defend it ⁴.
Another rarer visitor on migration is the White Wagtail Motacilla alba alba, actually a sub-species of the pied wagtail from mainland Europe. It is similar to a female pied wagtail, but with paler grey wings and other slight plumage differences. 

Pied wagtails nest in crevices, often in old stone structures such as old walls and tiled roofs and will use open-fronted nest boxes. Their small, cup-shaped nest is made of grass and moss. When the juveniles fledge, they are mainly a grey-brown with black throat and wing markings until their second year. Pied wagtails are typically short-lived, but the oldest recorded was 11 years old⁴.

This little city slicker is a delight to have around, and next time you’re on the streets on a Friday night, it just might be worth looking up at the trees.

*The others are the Grey Wagtail M.flava and the migratory Yellow Wagtail M.cinerea

 References

1-      Dominic Couzens. (2012) Garden Birds Confidential. Bounty Books.

2-      Fransesca Greenoak. (1979) All the Birds of the Air. A. Brown and Sons.

3-      Michael.J. Seago (no date) Pied Wagtail. Birds of Britain. Available from: http://www.birdsofbritain.co.uk/bird-guide/pied-wagtail.asp

4-      R.A. Robinson.(2005) BTO BirdFacts: profiles of birds occurring in Britain & Ireland: Pied Wagtail Motacilla alba   [Linnaeus, 1758]. Available from: http://blx1.bto.org/birdfacts/results/bob10200.htm

O is for Oystercatcher

OYSTERCATCHER (HAEMATOPUS OSTRALEGUS)

The Oystercatcher Haemotopus ostralegus is a very recognisable wader, with striking black and white plumage, scarlet bill and bright pink legs (the name Haematopus means ‘blood foot’¹, odd considering their beak and eyes are redder). They’re also one of the most common and easily seen, flying in loudly-peeping groups between feeding and roosting areas. 

Oystercatchers live in many coastal habitats, from rocky cliff bases to muddy estuaries across the British shoreline. Within the past 30 years some have moved inland upriver to gravel pits, flashes (shallow pools), and pasture, a phenomenon first noticed in Scotland². Some have even followed the example of urban gulls, nesting in cities and feeding in playing fields.

Oystercatchers are misnamed. Their original name was ‘Sea-pie’ after their pied feathers. Their current title is an Americanism, from the naming of its cousin the American Oystercatcher H. palliatus in 1731, which eats small oysters³.  Our oystercatchers rarely, if ever eat oysters, but they do enjoy shellfish, especially mussels. Another appropriate older name is ‘mussel cracker’³. Or it would be if they all cracked them...
 
The oystercatchers’ showy beak is very powerful *, allowing them to deal with hard-shelled prey, but their feeding habits differ. Some are ‘crackers’ or ‘hammerers’, bashing the shell until it smashes, whilst others are ‘stabbers’ prising the shells apart at the seam^1,2,4. Their tools match their trade, stabbers having slimmer, flattened beaks and hammerers being shorter and thicker. Still others are worm-eaters with thin, pointed bills for probing their burrows⁴.

These types have puzzled ornithologists since the 1960’s. They were once thought to be learned through generations. Unlike other waders which feed themselves from day one, Oystercatchers teach their offspring how to eat. The parents can be devoted teachers, spending over 6 months schooling their young. However, oystercatchers nesting inland often leave for the coast before their young can fly with them so their habits cannot just be learned⁵.

The truth is even more fascinating. Oystercatchers can switch their diets and are able to change their beak shape within days!  This is thanks to their beak growing at three times the rate of human fingernails, so it responds quickly to wear and pressures (Just like our muscles and bone build up through strain and tear). In a captive experiment, it took just 10 days for the beaks of mussel hammerers to change to worm-eater form when their diet was switched. This makes the oystercatcher very adaptable and able to exploit whatever prey is available⁴.

As well as molluscs and worms, oystercatchers also eat insect larvae, shrimps, crabs, small fish and even occasionally the eggs and chicks of small gulls (Though I could not find the original reference for this-see comments reference  4).
They don’t always catch their own food, often stealing from smaller waders. Some are professional pirates, getting 60% of their food from other birds⁶. But the world is not their oyster, as black-headed gulls Choriocephalus ridibundus and even juvenile oystercatchers steal ready-opened molluscs from the stronger adults⁴.

Oystercatchers nest in bare scrapes on a prominent feature such as a rock or in the open on shingle or short grass where they can easily spot predators and their pebble-like eggs are camouflaged. Urban oystercatchers take advantage of gravelled areas, including flat roofs.

Males protect the nest and are a force to be reckoned with. They react quickly to any passing nest predator, be it gull, corvid, raptor or human, flying up and chasing them away whilst shouting abuse. Other birds don’t want to get involved with the powerful beak.  When I visited Skomer Island with friends in summer, oystercatchers were constantly setting off after the many gulls and Buzzards Buteo buteo.  However, gull predation still greatly limits breeding success⁷.

Not all chicks are lucky enough to have their parent’s protection, since oystercatchers sometimes ‘egg dump’ –laying their eggs in the nest of another, like a gull. Whilst the female probably hopes her chick will be reared by its adopted parents like a cuckoo, its chances of survival are slim⁸.

Chicks that do survive to adulthood may live long and prosper. Some oystercatchers have been recorded at 30-40 years old^1,4.

Oystercatchers are certainly a unique wader. This pied piper of our shorelines may be common and  perhaps taken for granted, but is hugely adaptable and intriguing

*In fact, it has the heaviest beak of all living waders.

References

 

1- R.A. Robinson.(2005) BTO BirdFacts: profiles of birds occurring in Britain & Ireland: Oystercatcher Haematopus ostralegus   [Linnaeus, 1758]. Available from: http://blx1.bto.org/birdfacts/results/bob4500.htm

2- Peter Holden and J.T.R. Sharrock. (1989) The RSPB book of British Birds. PAPERMAC, London.

3- Fransesca Greenoak. (1979) All the Birds of the Air. A. Brown and Sons.

4- Darren Naish. (2010) The incredible bill of the oystercatcher. Tetrapod Zoology. Available from: http://scienceblogs.com/tetrapodzoology/2010/07/11/incredible-bill-of-oystercatcher/

5-William.J. Sutherland. (1987) Why do animals specialize? Nature 325, 483-484. Cited by: Darren Naish. (2010) The incredible bill of the oystercatcher. Tetrapod Zoology. Available from: http://scienceblogs.com/tetrapodzoology/2010/07/11/incredible-bill-of-oystercatcher/

6- Nicholas Hammond and Bruce Pearson. (1994) Waders. Hamlyn, London. Cited by: Darren Naish. (2010) The incredible bill of the oystercatcher. Tetrapod Zoology. Available from: http://scienceblogs.com/tetrapodzoology/2010/07/11/incredible-bill-of-oystercatcher/

7-M.P. Harris and S.Wanless. (1997) The effect of removing large numbers of gulls Larus spp. on an island population of oystercatchers Haematopus ostralegus: Implications for management. Biological Conservation 82 (2), Pages 167–171. Available from: http://www.sciencedirect.com/science/article/pii/S0006320797000190

8- Science Daily and Dr Clive Craik. (2011). Birds Dumping Eggs On the Neighbors. Available from: http://www.sciencedaily.com/releases/2011/05/110524203605.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29&utm_content=Google+Feedfetcher

See also Mike Mottram’s entry on filming an urban oystercatcher nest in ‘Diaries of a Cheshire Wildlife Watcher’

N is for Nuthatch

NUTHATCH (SITTA EUROPAEA)

With its powder blue upperside, blended cream and rusty orange underside and charcoal bandit mask , the Nuthatch Sitta europaea looks as if it has been coloured with pastilles, but is surprisingly difficult to see in its shady habitat. The nuthatch is truly a woodland bird, and with good reason. Like a woodpecker (which it resembles) it finds food on and under tree bark, hopping up, down and around the trunk and branches in search of insects. The nuthatch is the only British bird capable of climbing down a tree trunk head first. They achieve this through not relying on their tail as a prop, as woodpeckers and treecreepers Certhia familiaris do, and by having especially large, strong feet which they position one behind the other to act as a pivot and support¹.

The nuthatch reveals itself by its insistent piping call or the crackling sound of it pecking and peeling bark. Even then, they are difficult to keep track of as they scoot and weave behind the tree in and out of view.  However, they are quite tame and will call or feed a couple of meters away.

The nuthatch also eats seeds and nuts in autumn and winter when insects become scarce, cracking them by shoving them into a bark crevice and thrusting down with its powerful beak. This habit earned them their original, more powerful name ‘Nut hacker’ which has since become corrupted².

Nuthatches are partial to peanuts and seeds from garden feeders and bird tables, where they aggressively chase off other small birds, especially other nuthatches. Though they are increasingly seen in gardens where they are most easily observed, they only visit those near woodlands. Nuthatches stay very close to their birthplace, and even patches of suitable natural woodland may not be colonised if they are too far from others³. However, nuthatches are slowly moving North with warmer British weather, and were first recorded breeding in Scotland in 1989⁴

Perhaps because they don’t move far and because they nest in scarce tree holes, territory is very important to nuthatches. Neighbouring pairs have frequent stand-offs. Usually these are just posturing, but sometimes they escalate into fights when their beaks often inflict serious injury or death⁴.  Juvenile nuthatches have to wait in the wings in low-quality territories until a position in a breeding territory becomes available⁵. Though they are a small bird and reach adulthood at just 1 year, nuthatches have been recorded at 7 years old⁶.

Nuthatches are crafty birds. They store seeds and nuts for the winter by pushing them into gaps in tree bark or wood. Come nesting time, they will plug up their nest hole with mud, which hardens like concrete until only their bodies can pass through. This keeps out nest predators such as woodpeckers and competitors like starlings Sturnus vulgaris, but they can be over-enthusiatic, filling up the joins in nestboxes and even encasing them entirely ^1,3!
 I have also once seen one of a pair of nuthatches in Worcester use a piece of bark to prise off another part and wondered if this counted as tool use. This behaviour (this time with a small stick) has been photographed before.  Its American relative, the brown-headed nuthatch is renowned for using tools in a similar way.

Next time you’re in a woodland, make an effort to listen out for this agile and crafty character around a tree trunk near you.

References

1- Dominic Couzens. (2012) Garden Birds Confidential. Bounty Books.

2- Fransesca Greenoak. (1979) All the Birds of the Air. A. Brown and Sons.

3- Peter Holden and J.T.R. Sharrock. (1989) The RSPB book of British Birds. PAPERMAC, London.

4-Tim Harrison and Mike Toms. (2012) BTO Garden Bird of the Month – November: Nuthatch. Available from: http://www.discoverwildlife.com/blog/bto-garden-bird-month-%E2%80%93-november-nuthatch

5- Erik Matthysen.(1990) Behavioural and ecological correlates of territory quality in the Eurasian Nuthatch (Sitta europaea). The Auk, 107 (1), 86-95. Available from: http://www.jstor.org/discover/10.2307/4087805?uid=3738032&uid=2129&uid=2&uid=70&uid=4&sid=21102756365933

6- R.A. Robinson.(2005) BTO BirdFacts: profiles of birds occurring in Britain & Ireland: Nuthatch Sitta europaea Available from: http://blx1.bto.org/birdfacts/results/bob14790.htm

M is for Moorhen

MOORHEN (GALLINULA CHLOROPUS)

“Look there’s a moorhen.” said my schoolteacher.
“What’s a moorhen?” someone replied
“It’s a little, black duck.” he said.

The Moorhen is not a duck. Neither is it a chicken, but with their cocked tail and habit of strutting and pecking in the grass it is easy to see the resemblance. They are a rail, related to the Coot Fulica atra which they are often confused with.

The moorhen appears black, with a flashing white undertail and white stripe along the wing, but a closer look reveals its wings are dark brown. Offsetting their plumage, their pointed beak is a bright waxy red and yellow (The coot by contrast is all black with a white beak). When on land, the moorhen reveals its long, gangly legs and toes which spread its weight on aquatic vegetation or silty banks and propel it through the water.
The moorhen’s  loud, high-pitched voice is also very distinct. Their explosive ‘Pruuuk!’ call from a hiding place has often made me jump.

Moorhens are a familiar wetland bird, found almost anywhere there is fresh water from park lakes and marshes to small ponds, sometimes in gardens.  They are quite skittish and prefer to stay around bankside plants to hide from predators, though they often venture onto open lawns to feed. They are rarely seen flying, since they usually do it at night.They are generally most active in the evening.
Moorhens are omnivores, eating a variety of foods in water and on land,from algae, shoots, roots, fruits and seeds to invertebrates, small fish and amphibians, and human scraps if available.

For a waterbird, moorhens have unusual habits. They often roost, and even nest in tree branches and during freezing winters they may venture far from water to find food, sometimes ending up around garden bird tables¹.

Added to this, their breeding behaviour is quite remarkable among birds. To the casual observer, everything appears normal, since it is difficult to separate the sexes. Closer study shows that moorhens reverse normal avian gender roles.  It is the male who tends the eggs and young the most, whilst females compete for good father material. The male is also responsible for holding the family’s territory, providing a safe home to rear the chicks².

Another quirk to moorhen family life is cooperative breeding². Young from the year’s first brood may stay and help their parents raise later broods. Only two other British birds are known to do this, the Long-tailed Tit Aegithalos caudatus and the Swallow  Hirundo rustica. The parents obviously benefit from the reduced workload, and more chicks survive, but what’s in it for the stay-at-home teenager? By staying with it’s parents, the cooperative youngster avoids conflict with strangers in other territories, but also indirectly improves its gene pool. Since it shares genes with its younger siblings and can’t breed itself until adulthood, the helper actually improves its lifetime reproductive success (known as its ‘inclusive fitness’). See here for further explanation and photographs of this behaviour.

The moorhen’s nest is made of twigs, other plant parts and often plastic rubbish. It is usually built away from the banks to be out of reach of predators, either in the water or up to 8 metres above it in a tree.  Although it appears messy, the nest is meticulously woven together.
The chicks are very comical with messy black down, partly bald heads and feet that seem too big for their bodies, making them charmingly clumsy walkers. Juvenile moorhens are grey-brown with pale beaks reaching maturity at just one year old.

Though they seem dainty and skittish, Moorhens are ferocious fighters amongst their own kind.  Two aggressors rush towards each other and turn in a head-down display fanning their white undertails to show off their size. If neither backs down, they start a ferocious grapple, clawing each other’s heads and breasts with their long toes like fighting cockerels and ultimately aiming to dunk each other underwater. Most fights you will see during the breeding season are ‘cat fights’ between females over a choice boyfriend, whilst males fight over territory². See a dramatic video of both partners fighting here (video would not embed).

So next time you’re by the water and see a moorhen, look through the unassuming cover and admire the unique bird within, that will do anything for its family.

References

1-      RSPB Community Forum. (2010) Moorhen in the Garden!. Available from: http://www.rspb.org.uk/community/wildlife/homesforwildlife/f/905/p/7822/61771.aspx

2-      Africa Gómez. The surprising Moorhen. Available from: http://therattlingcrow.blogspot.co.uk/2010/03/surprising-moorhen.html