Recent Data from Sweden on Breeding Populations
Three sources are used below to build a picture of the current status and the trends in Honey Buzzard populations in Sweden over the last half-century:
Swedish study area in Dalsland
Home Page (mainly in Swedish, earlier versions of site were in English).
The breeding population was estimated as 5,000-6,000 pairs for the whole of Sweden in 1989.
In the seven years 1993-99 there was a strong negative trend with population down about 3-4% per annum and now under 5,000 pairs. Over a longer time span the population is apparently down one-third since 1986. In Dalsland, Sweden, the breeding population has fallen from 120-140 pairs in 1990 to a maximum of 100 pairs in 2000.
The numbers of juveniles ringed has declined in the 1990s in Sweden from c40 in 1990 to just under 20 each year from 1997-99. In Dalsland 95 juveniles and three adults were ringed from 1992-98.
In very recent work in Dalsland on 16 nest-plots, a number of active nests were found and monitored in 1999 and 2000. In the first year no young were fledged from five nests, in the second an average of 0.33 young was ringed per nest from nine nests. The comment for 2000 is: "Another year with very low reproduction level. But this year (as opposed to 1999) some breeding succeeded .... the results from the two latest years may be caused by not only food shortages but probably even that birds from our controlled plots have alternative plots/nests outside our control?".
The downward trend continued until 2007 when six pairs raised just one young. But overall there seems to be some bottoming out of the decline in recent years and to give some hope 2008 was better with 9 young from 8 pairs. The density of pairs was however quoted as declining from a maximum of 7 pairs per 100 sq km in 1992-94 to a maximum of 3 pairs per 100 sq km in 2006-08.
ArtDatabanken, Swedish Species Information Center,
Pernis apivorus, bivråk, Hökartade rovfåglar STARKT HOTAD (EN) A2bde
extract (Google Translation):
Range and status. Hedgerows in all landscapes except on the island of Gotland. The species is generally probably more common in the eastern parts than in the west. In northern Norrland's inland is very sparse existence. In the early 1980s estimated the Swedish population to about 8,000 couples, but would currently (2005) to be significantly less (around 5000 pairs). The number of annual autumn migratory Honey Buzzard in the standardized Migratory bird censuses in Falsterbo were on average 12 700 items. 1973-1980, 7650 items. 1981-1990 and 4500 1991-2000 (Nils Kjellén). During the years 2001-2003, the average only 2800 individuals. According to Falsterbo figures Honey Buzzard has thus fallen by 50-70% in the last 30 years (three generations). Honey Buzzard is a European and west Asian breeding bird. In parts of Western Europe existence sparse and uneven, at least locally declining. In England there are at most 70 couple. In Norway, Honey Buzzard small in the south-east and has gone back sharply since last century, while in Finland occur in the south up to 67 ° N (3000-4000 couple, decreased by 20% in 1990-2000). In Denmark hedges 600-700 couples, especially in the deciduous forest-rich eastern parts of the country. European population estimated at least 110 000 few of which about 70 000 in Russia.
Reproduction in eastern Svealand 1986-91 was 0.6 kids / couple studied (n = 99) and the proportion successful breeding of all the couples studied was 35%. A high proportion of bivråksungarna [young Honey Buzzard] becomes captured by Goshawk and marten (over 20% in East Svealand 1986-1991). The low reproductive rate is compensated by an average long life. The oldest known wild Honey Buzzard was 29 and 28 years old.
ArtDatabanken, MS Natural Facts
Responsible for guidance: Krister Mild, Environmental Protection Agency. krister.mild @ naturvardsverket.se
Background information from, inter alia: Mikael Svensson, MS Natural Facts, Martin Tjernberg, ArtDatabanken,
SLU. martin.tjernberg @ ArtData.slu.se
A072 Honey Buzzard (Pernis apivorus) Latest update: 2003-04-08
extract (Google Translation):
National conservation in 2001
Honey Buzzard hedges in all counties except on the island of Gotland. The Swedish stock has fallen more or less continuously for at least 30 years. Population size is very difficult to predict, but guess we have no more than 5 000 couples in the country.
Honey Buzzard is red-listed in Sweden and meet the criteria for placement in Endangered (EN). However, the disappearance risk downgraded to Vulnerable (VU) based on relatively good presence (but partially reducing) the rest of Europe, offering the opportunity to re immigration. Bird Life International describes as Honey Buzzard Secure in Europe. The species is located in SPEC Category 4, which means that the species' global population is concentrated in Europe and that the nature have a satisfactory conservation in the field (Tucker & Heath 1994).
National conservation (Not specified by the Environmental Protection Agency) The aim should be to stem the continuing decline observed over a long period and eventually to regain a population size that is in the vicinity of which were under 1960 - and 1970's (at least 10 000 couples). For this to succeed, measures must be implemented both domestically and internationally.
Discussion (NR)
So from the 1970s-2000s Swedish population and productivity is in rapid decline, giving very few juveniles to come here, and UK migration numbers soar.
When the Swedish population was perhaps double or even treble that of today, we had virtually none:
records of birds [Honey Buzzard] on passage are very few and irregular (at pp.141-142)
from The Rarer Birds of Prey, Their Present Status in the British Isles, British Birds 50(4) 129-155 (1957).
So when the Honey Buzzard does not breed in Britain, there's no passage.
But the Rough-legged Buzzard is reported by Witherby (1944) as “occurs most years ... and at intervals in considerable numbers”. So there was keen observation.
Also note above the recent sharp fall in Norway's Honey Buzzard population.
Nick Rossiter 2008
