British Birds: Some Decline While Others Increase….

Nightingale

In an earlier posting we noted that one species (Great Tits) of British birds was coping quite well with alleged climate warming. A report today in The Independent (U.K.) shows that, while many British birds are declining in numbers, others are increasing. Causative factors in decline included intensification of agriculture causing loss of farmland birds such as grey partridge and corn bunting; changing woodland management methods, increased deer populations, predation by grey squirrels, and problems on wintering grounds in Africa of migratory species as causes of declines in woodland birds. (willow tit -77%, wood warbler -67% etc).

Changes in vegetative undergrowth caused by deer browsing is listed as the most likely factor in the decline of woodland birds. The nation is seeing a rapid increase in deer population led by the muntjac, an introduced tropical deer.

The good news, however, is reserved for the so called garden variety birds: many are exhibiting substantial increases in numbers probably due to backyard feeding and warmer winters: (oh, oh there’s that climate warming bugaboo again!) great tit +55%, goldfinch +39%.

Great Tits Cope Well with Warming….

The blog title above is the actual headline from a BBC News article. The discussion is about how some British birds are coping (or not coping for that matter) with climatic changes. The Great Tit, for example is doing quite well, adapting to the earlier arrival of its Winter Moth caterpillar food by laying its eggs earlier. Thus the chicks have abundant food when they hatch. (from the article, emphasis added)

At least one of Britain’s birds appears to be coping well as climate change alters the availability of a key food.

Researchers found that great tits are laying eggs earlier in the spring than they used to, keeping step with the earlier emergence of caterpillars.

Writing in the journal Science, they point out that the same birds in the Netherlands have not managed to adjust.

Understanding why some species in some places are affected more than others by climatic shifts is vital, they say.