Sexing and ageing Rose-ringed Parakeets Psittacula krameri in Britain

Rose-ringed Parakeet (Psittacula krameri) Science Article 1

abstract

Although Rose-ringed Parakeets Psittacula krameri over three years old can easily be sexed due to the males’ rose-coloured neck-rings and black bibs, sexually immature males and females are considered impossible to separate in the hand. The biometrics of males and females overlap but males tend to be slightly larger than females in all measurements. We derived a discriminant function to separate the two sexes using wing length, bill length and the number of fully yellow underwing coverts. Biometrics were recorded for 235 individuals captured between February 2001 and May 2003. Feather and blood samples were taken from 45 of these birds to determine the sex by haplotyping. The measurements from these known-sex individuals (22 females and 23 males) were pooled with the measurements for adult males and a binary logistic regression function was derived which correctly separated 96.6% of the known sexes. The first data on moult patterns in Britain were obtained and are useful in ageing birds during the spring. In addition, it was found that the tips of primaries were rounder in adult birds than in juveniles, a result that agrees with other studies on parrots and some other bird species.

Christopher J. Butler and Andrew Gosler, Ringing & Migration (2004) 22, 7-12

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