Birds Adapting to Cold Conditions

Wednesday 16 January 2013, 15:50

Paul Stancliffe Paul Stancliffe BTO

Hibernation is something that birds just don’t do, not in the true sense of the word, but there are a few species that come pretty close, such as the Common Poorwill (North American Nightjar), which can spend weeks in a state of torpor during the winter months.

Swift-Chick-by-Graham-Roberts

Swift Chick by Graham Roberts

In the UK there’s one bird that occasionally goes into a sort of mini-hibernation during cold snaps in their breeding season.  Swifts arrive back in the UK around the end of April and immediately get on with the business of producing a brood of youngsters.  Swifts are supreme aerial feeders; when they have youngsters to feed they are on the wing all day, trawling for insects with their gaping mouths and turning them into a ball of protein to feed to their chicks. During very cold or wet weather these small insects are not so readily available and the adult birds have to forage farther away from the nest, sometimes hundreds of miles away.  Most young birds, such as tits or thrushes, would die without regular feeds but young Swifts can enter a state of torpor, reducing their metabolic rate in the hope that the weather will improve and food will be provided. 

Roosting-Great-Tit-by-Leo-du-Feu

Roosting Great Tit by Leo du Feu

Even common birds, such as Blue and Great Tits can change the way their bodies operate, so as to see them through tricky winter conditions.  On a nest camera, you can see just how spherical the body becomes, as feathers are fluffed up and the surface-area to volume ratio is reduced, and how the bill and head are tucked away, these being the parts of the body which lose most heat.  What you cannot see is that the bird also drops its temperature by as much as ten degrees, to further minimise heat loss. This is called nocturnal hypothermia; by reducing the difference between body temperature and outside temperature, the flow of heat from the body drops.  None of our wintering birds use torpor, which would also involve reducing the metabolic rate.

Cuckoo-by-Steve-Ashton

Cuckoo by Steve Ashton

The main strategy for coping with the extremes of cold weather is to move, and many of our birds do just that – not that it is an easy option though. Some of the birds that visit us for the summer months travel huge distances to suitable overwintering areas, journeys that can be incredibly hazardous. The BTO satellite tagged cuckoos brought this home in 2012 as the five birds tagged in 2011 struggled to get back to the UK to breed, and birds that were tagged in the summer of 2012 struggled to make it to Africa. Fortunately, five of the birds did manage to find enough food at their stopover sites and avoid the summer storms, making it back to the mighty Congo Rainforest, Including Chris, the BBC Springwatch cuckoo.

You can follow these birds at http://www.bto.org/science/migration/tracking-studies/cuckoo-tracking

Comments

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  • rate this
    0

    Comment number 1.

    I have three bird boxes in my garden, would birds use these at all as shelters during bad weather, I never see any activity , just wondered as they are dry and sheltered

  • rate this
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    Comment number 2.

    Outside of the breeding season, nestboxes provide excellent shelter, not only for roosting but also from bad weather. So, if your nestboxes aren't being used to raise a family, they still provide an important resource.

  • rate this
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    Comment number 3.

    Oh dear, still can't do it can you

    Producers; Presenters (apart from Euan that is).

    Here is your challenge for this evenings programme.
    Try saying the following
    1. Van GOGH with the emphasis on the german ich sound, ( see your own website for guidance http://www.bbc.co.uk/blogs/magazinemonitor/2010/01/how_to_say_van_gogh.shtml
    2. Bach as in the composer with emphasis on 'ch' sound again
    3. or like the j in Rioja, the Spanish wine.

    Now try saying LOCH properly please !

  • rate this
    0

    Comment number 4.

    We have a pair of Blackcaps coming to our garden everyday feeding on an insect fat slab. pretty birds, nice to see them. We live near woodland and have a number of large trees around our garden.

  • rate this
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    Comment number 5.

    I've seen as many as 10 wrens piling into one of our nest boxes on chilly nights. Would that be the same box as they hatched in or do they use any box? We have about 20 boxes all over the garden and it is impossible to keep an eye on them all. As the weather has now got much colder we have jays, greater spotted woodpeckers, green woodpeckers and nuthatches all coming to the feeders. I am surprised the resident pheasant hasn't had a heart attack by now as the Poodle dashes out and surprises it.

  • rate this
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    Comment number 6.

    It is well known that Wrens roost communally in nest boxes, and the record number found using a single box stands at 62. These birds will choose a nestbox that provides them with the warmth and shelter they need to get through a cold winter night and so will use any box that meets these conditions.

  • rate this
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    Comment number 7.

    We live in Shoeburyness in Essex and have a very bird friendly garden. So far this year we have had Winterwatch and Springwatch at the same time in the garden. So far we have a Grey Wagtail and a Goldcrest visit us on several occasions. Our Springwatch is that our pair of resident Robins have built a nest in a dwarf conifer by the pond. How is that for optimism? However I think that they have shock coming!

  • rate this
    0

    Comment number 8.

    Four Great Spotted Woodpeckers outside my flat window this morning! Have woods with lots of oak trees nearby which they favour. Amazing! They were bouncing and flying at each other, playful I think!

 

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