NatureWatch

Geoff Hill

With three more Bri sh birds added to the red list of endangered species in the survey issued in December 2021, the number reached some 30% of the total. It seems an appropriate me to consider how climate change might affect the future numbers and mix of wild birds. Climate change has already had an effect which is likely to increase as temperatures con nue to rise. We will face ho er summers with more extreme droughts, and warmer and we er winters with more intense storms.

It is quite possible that we will end up with more birds in total as the breeding season has already lengthened and will con nue to do so. The spring is arriving ten days earlier and autumn occurring ten days later than in the 1950s. A downside to this, par cularly for migratory birds, is that insect popula ons may no longer peak at the point at which chicks are hatching. The number of migrant birds has also dropped because their feeding grounds en route in southern Europe are suffering a greater number of droughts. This is one reason why swi s have been added to the red list.

Rare species, unfortunately, may be dispropor onately affected. They are o en rare because they seek specific food sources or habitats, both of which could disappear. The ptarmigan is moving to higher and higher ground and will eventually get to the top of the mountains. Some birds will prosper. The wood pigeon which can breed successfully at any average temperature from 13° C to 30°C is likely to increase in numbers to the horror of gardeners and farmers alike.

Higher temperatures also mean some birds that have tradi onally migrated in the winter are no longer doing so. Black-caps and chiffchaffs are now staying rather than over-wintering in southern Europe. Scandinavia will have an even greater rise in average temperatures than the UK because it is nearer to the Arc c. Millions of blackbirds, robins, chaffinches and other species from northern Europe may no longer need to over-winter in the UK.

Seabirds will be affected by warmer seas which is causing their food sources to move North. Puffin popula ons are already falling because of a lack of sand eels. Rising sea levels could mean that the mudflats on which wading birds depend may no longer be exposed at low de.

Southern England in par cular will become warm enough to be a regular breeding ground for species only seen very occasionally here such as the ca le egret and the great egret.

Popula ons may fluctuate very widely from year to year. An intense storm at the wrong me could decimate migrants such as geese in-flight while intense heat could easily result in chicks dying from heatstroke.

To date most of the calamitous collapse of wild bird popula ons has been the result of two factors, loss of habitat and a drop in insect popula ons due to intensive farming. If these two problems can be tackled, this would go a long way to mi ga ng the impact of climate change.