Rufford, Lancashire, Regno Unito, 15th gennaio 2016. Meteo E Fauna Selvatica. Un 'Trang di Crows' cerca i rami più alti per riscaldarsi all'alba dopo una notte gelida al porto turistico. Migliaia di corvi posero ogni notte in comune, riunendosi al crepuscolo e atterrando prima nelle aree di sosta prima di entrare nell'area principale di rosting. Nessuno sa ancora perché corvi throng insieme in numeri così grandi; si può solo indovinare.
3600 x 2400 px | 30,5 x 20,3 cm | 12 x 8 inches | 300dpi
Data acquisizione:
15 gennaio 2016
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Many species of birds gather together at dusk in preparation to spending the night in a large group, or roosting for the night. Sometimes there are thousands of individual birds in these groups. No one knows exactly why various species of birds do this. One possibility, of course, is the idea of safety in numbers. By gathering in very large groups the risk of any individual bird falling prey to a nocturnal predator such as an owl becomes very low. Another possibility relates to the observed fact that this behaviour, especially in some species, is more common in winter. That is by gathering in large groups the birds moderate the effects of cold weather with the collective heat of massed bodies. During the day, the crow population may be spread out over a very wide area, but perhaps an hour or more before dusk, birds will begin to fly towards the roost, collecting together into ever larger flocks as they get nearer. Generally, it seems as though most birds do not fly directly to the communal roost, but stop at nearby "staging areas". As dusk approaches, the birds will abandon the staging area and gather in the communal roost. Often every suitable branch on every tree for a considerable distance will have a crow occupying it and there are constant alarms and mass flights and continual interactions of birds both in flight and in the trees. The noise level can be tremendous. As it grows dark the birds settle down and remain quite until dawn when they disperse again. Almost nothing is known about why crows form these communal roosts or of the dynamics of the populations involved. It appears that crows will travel considerable distances to a roost, but that not necessarily every crow in an area will travel to a particular roost every night.
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