Wednesday, April 22, 2009

What Is Good For One, May Not Be Good For Another

Mediterranean Gulls

The Rare Breeding Birds Panel (RBBP) located in the UK was started in 1973. I know some of my readers are birders and this website is unbelievable. Hurry your little mouses (or is it meeces?) over there and check it out!

Anyway, back to story at hand. The numbers of little egrets, firecrests, cranes and Mediterranean gulls are at their highest since monitoring began by the RBBP. While this may be good news for some rare and endangered species, it is having a negative impact on other species.

As every good scientist knows: For every action – there is an equal and opposite reaction. Or as my mother often says: Swings and roundabouts, swings and roundabouts.

According to the 2006 Rare Breeding Birds survey (the latest information available) showed little egrets increased to 434 breeding pairs with the actual population estimated at approximately 600 pairs.

The firecrest reached an all-time high of 341 pairs. This increase in numbers is thought to be a combination of warmer weather and the increase in plantations which provide them with a suitable habitat.

Mark Holling, secretary of the RBBP, said the firecrest was "a species which has found new habitat and a climate to suit", although the most recent cold winter may have reduced numbers.

According to the study, milder winters have also benefited the Wood larks, Cetti’s warblers and Dartford warblers. The opposite reaction is the warmer weather may be having a negative impact on some northerly species, such as the Purple Sandpiper and Temminck’s stint. The study was only able to record one bird of each species in 2006.

Mr. Holling said it was "tempting" to conclude these birds, which breed in the Scottish Highlands, were affected by mountainous areas becoming less cold. There appears to be a shrinking of populations which are more northerly and an increase of birds which have come to us from the continent."

There were some surprises found in the report. Some species which researchers expected to benefit from the warming trend had; in actual fact, declined. Species such as the Golden oriole, Marsh Warbler,Wryneck did not even appear in the study.

Mr. Holling said the decline of Golden orioles may be environmental in cause. There has been a recent increase in the felling of the poplar plantations these birds favour as a habitat.

"It might be getting warmer: but, if their habitats have been degraded, they can't find the spaces to successfully breed," he said.

Mark Eaton, a senior conservation scientist at the RSPB and a member of the RBBP said: "The report is further proof that our bird populations are changing. Avocets, Mediterranean gulls, firecrests and Cetti's warblers all enjoyed their best year on record; but, a century ago these species weren't even breeding in Britain. However the report shows that the wryneck, which was formerly one of our more widespread birds, is slipping closer to extinction, as for only the second time on record no breeding records were reported during the year."

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