Rook (Corvus frugilegus) - unusual colour form?

SAM 9013

During wetland survey work at Lakelands, in Naas town, Co. KIldare I came across this unusal Rook (Corvus frugilegus). Not sure what causes the unusual colour form - and when i first saw the bird in flight I thought it was some sort of a bird of prey !

Seems the explantion below might explain the unusual colour: 

Leucism, or leukism, is an abnormal plumage condition caused by a genetic mutation that prevents pigment, particularly melanin from being properly deposited on a bird’s feathers. As a result, the birds do not have the normal, classic plumage colors listed in field guides, and instead the plumage have several color changes, including:

  • White patches where the bird should not have any
  • Paler overall plumage that looks faint, diluted or bleached
  • Overall white plumage with little or no color discernable

The degree of leucism, including the brightness of the white and the extent of pigment loss, will vary depending on the bird’s genetic makeup. Birds that show only white patches or sections of leucistic feathers – often in symmetrical patterns – are often called pied or piebald birds, while birds with fully white plumage are referred to as leucistic birds.

For more info see: http://birding.about.com/od/identifyingbirds/a/leucism.htm

More about Marsh Fritillary on Bull Island

On 1 June 2013 took another outing to the Bull Island to examine the dune slack area where Marsh Fritillary larvae were observed in the autumn of 2012. During the visit more than 50 adults butterflies were observed in the dune slack, as well as a number of larvae beginning to pupate and even a single pupa. 

It would appear that the species has managed to cope with the poor spring weather this year and is set to start another year on the Bull. 

SAM 8860
SAM 8845
SAM 8817

© Peter Foss 2012