title: Reproductive success of rose-ringed parakeets Psittacula krameri in a captive UK population.
abstract: BACKGROUND
  Rose-ringed parakeets Psittacula krameri (Scop.) have recently become established in several European countries, with potential for significant negative economic and ecological impacts. However, in northern Europe the potential for reproductive output is largely unknown. In 2005 the authors established a captive outdoor colony in north-east England and examined breeding success over 2 years.
  
  
  RESULTS
  In 2006 (19 pairs, 15 clutches) the average first clutch size was 3.6 (+/-0.3) eggs. Six clutches were infertile, and overall the colony produced 1.4 (+/-0.5) fertile eggs per pair. Eleven pairs produced a second clutch following removal of the first; seven were infertile, and overall productivity was 0.7 (+/-0.4) fertile eggs per pair. Unsuccessful pairs were rearranged or replaced. In 2007, overall productivity was 2.5 (+/-0.4) and 1.8 (+/-0.4) fertile eggs per pair for the first and second attempts respectively. For pairs that remained unchanged through 2006-2007, productivity was consistent between years and breeding attempts.
  
  
  CONCLUSIONS
  Where food and nest sites were not limiting, clutch sizes in north-east England were similar to those in the native range, and consistent between first and second attempts. This has implications for the future expansion and management of the species.
authors.affiliation: The Food and Environment Research Agency, Sand Hutton, York, UK. mark.lambert@fera.gsi.gov.uk
authors.forename: Mark S
authors.initials: MS
authors.lastname: Lambert
authors.forename: Giovanna
authors.initials: G
authors.lastname: Massei
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bell
authors.forename: Leslie
authors.initials: L
authors.lastname: Berry
authors.forename: Carol
authors.initials: C
authors.lastname: Haigh
authors.forename: David P
authors.initials: DP
authors.lastname: Cowan
mesh_terms: D000818:Animals; D001947:Breeding; D004739:England; D005260:Female; D008297:Male; D046409:Psittacula / Q000235:genetics / Q000502:physiology*; D012098:Reproduction