Heat Wave and Birds

https://ww2.rspb.org.uk/community/wildlife/f/13609/t/82953.aspx

Unless you have been living under a rock for the past month you will be abundantly aware of the heat-wave Britain is currently experiencing. Normally I am writing about long winters or prolonged snow but warm weather can be as disruptive.

Birds lack sweat glands and so are unable to sweat to lower their temperature, instead, they must cool their body temperature via respiratory regulation and use behavioural changes. A bird’s natural body temperature is naturally higher than a mammal, between 37.7-43.5⁰C.

If the temperature of the air exceeds 38⁰C (which thankfully it isn’t in this heatwave) then birds actually undergo extreme stress which actually increases the body temperature until it dies. So to avoid this, birds undertake 3 cooling methods.

1.       Non-evaporative cooling – by raising feathers and spreading them out air is allowed to flow over the skin and cool the bird.

2.       Cutaneous cooling – as well as wind cooling the skin, can be cooled by water evaporating, due to the lack of sweat this is a lot slower but can be improved if the bird baths.

3.       Respiratory evaporative heat loss – This is seen as panting and many species of bird do this. By flushing their throat tissue with blood their allow heat to dissipate.

Birds will take behavioural changes such as seeking shade or sitting with their back to the sun, their feathers raised.

It is just as important in the summer to keep feeding the birds. Energy is needed to thermoregulate and sometimes heat waves cause scarcity of local resources. It is important to provide water baths and troughs for them to drink from, ponds are especially valuable.