|
WHAT DO THESE RESULTS MEAN? There are quite a number of different factors that we have to take into account when looking at these results. Obviously, there are some slight differences in the ways that people carried out their recording and there will have been local variation in the weather and overnight temperatures that may have altered the birds' behaviour. Fortunately, mass participation surveys like this one, help us overcome many of the biases that sometimes creep into ecological surveys - the large number of responses give a stronger underlying trend and lessen the effects of 'unusual' responses. Early risers... It is interesting to see Blackbird, Robin and Song Thrush in the top four early risers and this result is perhaps not that unexpected, given that all three species are known to sing at night in areas where there are street lamps. In fact, virtually all reports of Nightingales from urban areas are really of Blackbirds, Robins and Song Thrushes! Many notes from observers referred to the calls of Blackbirds heard while it was still very much dark. Even more interesting, is the presence of Dunnock (5th) and Wren (6th) so far up the list. Both of these birds are quite elusive in gardens, preferring to feed in cover and only rarely venturing onto the bird table. Their early presence at garden feeding stations might reflect an avoidance of more competitive and aggressive feeders like Greenfinch and Starling. Of course, for a small bird like a Wren (and for that matter Long-tailed Tit (11th), Blue Tit (3rd) and Coal Tit (12th) the long winter nights may have been very demanding energetically, making an early visit to the bird feeders all the more important. Stay in beds... Perhaps the most interesting finding from the survey is the late arrival of the larger and more dominant feeders like Goldfinch, Greenfinch, Starling and Wood Pigeon. These larger birds often arrive in flocks and dominate bird tables and feeders to the exclusion of other species. Are they arriving at a time that is optimum based on energetics and predation risk, relying on the fact that they can dominate the smaller tits and other birds? Huge roosting flocks are a familiar sight in some urban centres and the birds chose sheltered spots in which to roost before dispersing in the morning in small groups to search for food. In this way, they may minimise the amount of energy they have to expend overnight to keep warm, allowing them a later start the next day. We would also expect to see some regional differences and this is something that we will be looking at in greater detail as part of the full analysis. One of the questions we hope to address is whether birds in Northern Britain get up at the same time (relative to the time of first light) as those further south. Given that the nights are longer further north, we might predict that small birds actually have to get up earlier further north, relative to the time of first light, because they will have used more energy overnight trying to keep warm. With luck we should have more information on this early in the New Year. To find out more about where we go next click here.
|
|
|
|
Garden
BirdWatch | BTO
Home | CJ
WildBird Foods Home |