Species Up­date

Buz­zard num­bers in have in­creased dra­mat­i­cally in the UK since the 1990s, but will this trend con­tinue?

Bird Watching (UK) - - Contents -

Kate Risely on the buz­zard, whose pop­u­la­tion has boomed since the nineties

IOFTEN SEE BUZZARDS near my home; small groups soar­ing in clear spring­time skies, or sin­gle birds sit­ting im­pas­sively in the roadside trees. British Buzzards are res­i­dent, oc­cu­py­ing ter­ri­to­ries roughly a kilo­me­tre across all year round, so the birds I see must nest nearby; it’s ex­cit­ing to think that in a tree very close to home there will be a mas­sive Buz­zard’s nest, at least a me­tre across. There aren’t ac­tu­ally that many large trees here in the open, arable land­scape at the edge of the Fens, and I of­ten look through the small copses, won­der­ing where they might be nest­ing. For 10 years now, Buzzards have been Bri­tain’s com­mon­est bird of prey, with a pop­u­la­tion es­ti­mated to be in the range of 57-79,000 breeding pairs. This makes them even more abun­dant than Kestrels and Spar­rowhawks, with pop­u­la­tions of 46,000 and 35,000 pairs re­spec­tively. Bird At­las maps show that they are present in 90% of 10km squares in Great Bri­tain, ab­sent only from large ur­ban cen­tres, and more sparsely dis­trib­uted in ar­eas with few trees for nest­ing, such as the Scot­tish High­lands and in East Anglia. They are less com­mon in Ire­land, found only in east­ern parts. The re­cov­ery of the pop­u­la­tion to th­ese high lev­els has been one of the most com­plete and ex­tra­or­di­nary suc­cess sto­ries of any bird in re­cent times. Once wide­spread, they were wiped out from large parts of the coun­try due to per­se­cu­tion dur­ing the 18th, 19th and 20th Cen­turies, loss of their Rab­bit prey fol­low­ing the Myx­o­mato­sis out­break of the 1950s, and poi­son­ing by organochlo­rine pes­ti­cides in the 1950s and 1960s. They were driven back to strongholds of Scot­land, Wales, the South West and Cum­bria. By the end of the 1960s, all of th­ese pres­sures were lift­ing, and Buzzards started to make a come­back. Since 1990, num­bers have sky­rock­eted. Ac­cord­ing to the Breeding Bird Sur­vey, their pop­u­la­tion has in­creased by 80% across the UK over the last 20 years; this over­all fig­ure in­cludes a 182% in­crease in Eng­land, while num­bers in Scot­land and Wales have re­mained rel­a­tively sta­ble. Their in­cred­i­ble re­cov­ery, once re­leased from per­se­cu­tion, is tes­ta­ment to the adapt­abil­ity of this species. As I have seen for my­self at home in East Anglia, they can thrive in in­ten­sively man­aged The BTO runs vol­un­teer sur­veys to mon­i­tor and ex­plain changes in bird pop­u­la­tions. To find out more about the Wa­ter­ways Breeding Bird Sur­vey visit habi­tats; like Red Kites, they are rel­a­tively gen­er­alised in their diet, tak­ing their food where they can find it. They pri­mar­ily feed on mam­mals such as small Rab­bits and voles, but they will take a very wide range of other foods such as birds, snakes, frogs and earth­worms. They hunt prey on the ground, and the birds they take tend to be fledglings or ground-dwelling species; they will even take Wrens, pre­sum­ably due to their mouse-like ap­pear­ance. In North­ern Ire­land, there are no Bank Voles, and Buzzards here take a much higher pro­por­tion of birds, par­tic­u­larly crows. Over­all, how­ever, Rab­bits are by far the most im­por­tant com­po­nent of their diet, and fluc­tu­a­tions in Buz­zard num­bers can of­ten be linked to out­breaks of Myx­o­mato­sis or other Rab­bit dis­eases. Per­haps con­trary to the gen­eral per­cep­tion, re­sults from the Breeding Bird Sur­vey, which also cov­ers com­mon mam­mals, show that num­bers of Rab­bits in the wider coun­try­side have de­clined over the last two decades. For now, the in­crease in Buz­zard num­bers shows no signs of slow­ing, but it re­mains to be seen whether this adapt­able preda­tor will reach the lim­its of food avail­abil­ity.

Kate Risely is the British Trust for Or­nithol­ogy’s Gar­den Bird­watch Or­gan­iser

Their in­cred­i­ble re­cov­ery, once re­leased from per­se­cu­tion, is tes­ta­ment to the adapt­abil­ity of this species

SOAR­ING Buz­zard num­bers are in­creas­ing, but Rab­bit avail­abil­ity will be key to fu­ture suc­cess

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