MIXED FORTUNES FOR OUR BIRDS OF PREY

GONHS publishes survey results

The Gibraltar Ornithological & Natural History Society reports mixed results in its annual census of nesting birds of prey on the Rock.  Four species are now surveyed annually by the GONHS Bird of Prey unit, led by Vincent Robba.  These are the Peregrine Falcon, the Common Kestrel, the Lesser Kestrel and the Little Owl, with observations on Tawny Owls and Eagle Owls also being taken into account.

The Peregrines managed to raise more young (14) than last year  (7), although numbers are still down on recent maxima of 20 (2009) and 23 (2006).  Disturbance is probably a contributing factor.  Worryingly, these 14 young were raised by only six pairs.  One pair has disappeared altogether.  This pair occupied an eyrie in the area of Mediterranean Steps and was absent for the first time since the annual surveys began in 1974.

Lesser Kestrels raised 31 young to fledgling, but only 13 nests produced young, the smallest number since 2004.  Several nests have been taken over by feral pigeons.  Another concern is that a number of young were found dead at the base of their nesting cliffs on the North Face, apparently predated by cats.  The plight of these globally threatened birds needs to be addressed.  GONHS has long identified these problems and prepared a Species Action Plan within its  Gibraltar Biodiversity Action Plan published in 2006, but no measures have yet been implemented by Government.

Common Kestrels raised a minimum of 30 young, from a minimum of 9 occupied nests, two fewer than last year.  Eight Little Owl nest sites were identified, the same number as in 2010.  Eagle Owl nests were not located, but there was some evidence of the presence of the species in its usual locations.  However, the presence of Tawny Owls has greatly reduced, with no contacts in the latter part of the nesting season in the South District or the Botanic Gardens.  A concern is that the liberal use of rat poison may have caused casualties in this species through secondary poisoning.

Birds of prey continue to nest on the Rock with no assistance.  We are lucky that they have survived, but the annual censuses detect problems in some cases which need to be tackled if they are to continue to live here.

Photos by Paul Acolina/GONHS