From Wildlife Extra, about Britain and Ireland :
16/12/2009 08:51:53 Mixed fortunes for crests
Goldcrests and Firecrests have experienced very mixed fortunes this autumn.
Goldcrests – Very low numbers
Several Bird Observatories have reported a distinct lack of Goldcrests, backed up by anecdotal reports from many birders. The apparent population crash is reflected by the BirdTrack reporting rate which shows that they have featured on less than half the complete lists than normal for this time of year. Last winter was the coldest for 12 years and the very low temperatures both here and in Scandinavia seem the most likely cause for the decline.
Firecrests – Population boom
In contrast, it has been an excellent autumn for Firecrests. During September, October and November there were 23% more reports on BirdGuides than 2008. The difference between the two crests’ fortunes is probably attributable to the more southerly distribution of Firecrest, meaning that a smaller proportion of the population suffered the effects of the exceptionally cold winter 2008/09.
Birdtrack Goldcrest report.
Birdtrack Firecrest report.