Courtesy of WWT, for info;
'Results from age assessments made at wintering sites in the UK indicate that breeding success of Dark-bellied Brent Geese in 2007 was higher than in the previous year, and above the most recent ten-year mean (9.9% ± 2.96 s.e.). There was a marked increase in the number of broods observed compared with 2006 and the mean brood size was also higher, reflecting the improved breeding success.
The breeding success of Dark-bellied Brent Geese has previously been shown to follow a three-year cycle of good, poor and variable success (Dhondt 1987), and is greatly influenced by interactions between lemming abundance, predator pressure and other factors such as weather. In 2007, though only a few reports are currently available, monitoring stations along the Taimyr and Yamal Peninsulas in Russia indicated that lemmings were present in variable numbers (low numbers at the Yamal; common to abundant at the Taimyr), and Arctic Foxes were rare or absent (Soloviev & Tomkovich 2008). Between the mid 1990s and 2005, whilst there was still considerable annual variation in Brent breeding success, the pattern shifted away from a predictable three-yearly cycle, and there were fewer than expected good breeding seasons. This suggested that the connection between rodent abundance and breeding success may not have been functioning in the same way, or that rodent abundance was not following such a predictable pattern. Over the most recent three years, however, breeding success has been good (28.4% young in 2005), poor (2.0% young in 2006) and variable (11% in 2007). This also follows a similar pattern to that of lemming abundance at the breeding grounds, which saw exceptionally high numbers in 2005, a crash in 2006, and a variable year in 2007. These results suggest that breeding success may be returning to the more predicable three-yearly cycle; it will, however, take a few years of further monitoring to establish whether this is the case.'
So much for returing to the three year cycle - this is supposed to be a good year!
John
_________________ -------------------------------  Contact: recorder_south@lincsbirdclub.co.uk
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