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Wednesday, 24 August 2011

Eat! Roost! Bathe! Nest! The role of humans in everyday bird-life

The last couple of months have seen my posts taking on a distinctly invertebrate-centric flavour, so to balance out the ecological spread a little, I thought I'd have a look at some vertebrates, in particular the everyday interactions between birds and people. I don't want to cover the broader areas of nature conservation for birds - there are many excellent websites already doing this, such as the RSPB's page on farmland bird conservation. In a previous post I also looked at the effects of urban noise on birds. Instead I would like to share some examples of simple actions having positive effects, and others where birds have begun to adapt to the human-dominated world in which they find themselves (and not just the use of roadkill by crows).

A species well-used to intereacting with humans - the mallard Anas platyrhynchos relaxing after a hard day of being fed by passers-by in Winchester, southern England.
One place where many of us experience wild birds, and often help them out, is in our gardens. This is something that hasn't gone unnoticed, hence the popularity and importance of projects such as the RSPB's (yes, them again) Big Garden Birdwatch which attracts hundreds of thousands of volunteer recorders and counts millions of birds in the UK alone. So, what do our gardens provide?

A male blackbird Turdus merula hunting for invertebrates in our garden. Digging often brings a bold female right to our feet as she looks for earthworms.
On the simplest level, gardens provide habitat i.e. a replacement for what was there prior to urban development. Since the photo above was taken, our garden has changed a lot - the boring lawn has been largely dug up to create flower and vegetable beds, with the remainder being allowed to form a small 'wild' meadow. However, species such as the blackbird are still frequent visitors and I suspect that the increased structural diversity is beneficial (more invertebrates = more food for insectivores). Of course, this isn't all we do - 'supplementary' feeding is very important to a range of species (which tends to increase during harsh weather) and has the added benefit of bringing birds closer to us, giving us the opportunity to watch them and their behaviour at close quarters.

L-R: siskin (Carduelis spinus), redpoll (Carduelis flammea) and goldfinch (Carduelis carduelis) - three congenerics together on a nyger seed feeder.
A blur of activity - a mob of long-tailed tits (Aegithalos caudatus) in a squirrel-proof feeder.
 Of course, it's not just food - with the loss of many natural sources of water such as ponds (something that can only get worse with predicted hotter, drier conditions as climate change bites), water is also key. We can create ponds in gardens and elsewhere (we're in the middle of digging ours) and, even more easily, ensure regularly topped-up bird baths are in place.
A blackbird taking the opportunity for a drink.
A wood pigeon (Columba palumbus) hogging the bird bath and having an enthusiastic splash! Smaller birds have been seen waiting in nearby shrubs for pigeons to finish their ablutions.
 Sometimes water isn't what's required for bathing - sometimes it needs to be dry and sunny...

A juvenile robin (Erithacus rubecula) sun-bathing in an old chimney-pot, originally put in the garden to grow tomatoes.
Afterwards, time to cool off...
...while a beady-eyed adult looks on.
So, we've covered food and water - but what about shelter? Bird-boxes are familiar so I won't cover them here, however birds sometimes manage to make their own good use of structures put in place by humans for entirely other purposes.
A female house sparrow (Passer domesticus) just beneath a telephone junction box outside our house. Males and females have been seen taking nest materials and food into this box.
Three juvenile swallows (Hirundo rustica) in a nest built under the roof of a visitors' gantry at Monkey World Ape Rescue Centre in Dorset, southern England. Adults made frequent feeding visits to the nest, even flying between people as they came in through the open sides of the walkway. Apologies for the poor photo - I didn't want to disturb the nestlings by using the flash.
It looks like a model, but it was definitely real - one of the adult swallows at Monkey World, unusually seen perching.
 Sometimes of course, all that is needed is a quiet place away from too much human disturbance.

A family of mute swans (Cygnus olor) with juveniles developing after having nested in the middle of a rural riverside footpath. Unsurprisingly the adults were aggressive if approached at the nest, but a little understanding (i.e. a willingness to take a minor detour) was all that was needed.
A dipper (Cinclus cinclus) in its familiar position, looking for aquatic invertebrates from a rock in a stony stream. This looks like it could be an isolated moorland stream, but is in fact in the town of Lyme Regis, Dorset, southern England. There's a footpath alongside the river, but the dipper has become used to people who of course don't tend to wade into the water.
So, we have seen some brief snapshots of some of the ways in which birds benefit (or at least don't suffer) from the presence of thoughtful humans. This has not always been the case - until 1832, the world's heaviest flying bird, the Great Bustard Otis tarda nested in Britain, but subsequently became extinct here, probably due to a combination of hunting, pressure from increased human population and changes in land use (Waters & Waters 2006). 
A mounted specimen of the Great Bustard, a male with a splendid 'tache.
This is an unusual example, but one which shows a more positive recent trend as there is now a well-known reintroduction programme. The Great Bustard Group (which can be visited for a small fee) manage this through introductions from Russia and in 2009, after a gap of 177 years, Britain had wild Great Bustard chicks! Currently the effects of humans on birds vary - there have been huge declines in farmland and trans-Saharan migratory species (though even this has shown an improvement where there has been improved management in Africa), while many woodland species in Britain have increased, not to mention some complex trends relating to garden bird feeding. The conclusion - aside from getting involved in wider-scale conservation efforts, we can all act as individuals by making the places we live (and work?) in more attractive to birds and other wildlife. 'Nuff said!

Reference

Waters, E. & Waters, D. (2006). The Great Bustard (2nd ed.). Great Bustard Group, Salisbury.

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