lunes, 26 de diciembre de 2011

Egret roost


Followers of this blog may recall that a census of overwintering Ardeidae was carried out on La Palma at the end of January 2011, and coordinated throughout the country by SEO/Birdlife (see: Annual Ardeidae Census - RESULTS, posted on 26 Jan 2011 for more details). The census method entailed localising communal heron and/or egret roosts and simply counting the number of birds flying in at dusk to spend the night there. 

The first of the two main roosts on La Palma was located along coastal cliffs between Puerto de Tazacorte and Tijarafe, on the west coast of the island, and the second in a banana plantation bordering an irrigation pond, in the Tazacorte municipality. At the two roosts, 51 and 52 Little Egrets (Egretta garzetta), plus 5 and 1 Grey Heron (Ardea cinerea) were recorded respectively.

For the January 2012 census, an inspection of the coastal site is pending to see if it is still in use, but the plantation roost in Tazacorte now appears to have shifted to another group of irrigation basins about one kilometre away. On the evening of December 21, I counted 44 Little Egrets and 4 Cattle Egrets (Bubulcus ibis) at this newly-discovered location. The birds start flying in from about 18h onwards, with the peak of activity between 18:30 and 19:00. At this time of the year, from about 19:15 onwards, failing light makes further counting unreliable.

The short video posted above gives an idea of the lively atmosphere as the birds squabble for places on the flimsy, swaying branches of a Nicotiana glauca bush overhanging the pond... (Apologies for the rather poor quality of the film).

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