AVIS-IBIS

Birds of Indian Subcontinent

Age ratios in a Bullfinch Pyrrhula pyrrhula population over six years

Publication Type:Journal Article
Year of Publication:1999
Authors:Newton, I
Journal:Bird Study
Volume:46
Date Published:1999
ISBN Number:0006-3657
Keywords:Fringillidae, Pyrrhula, Pyrrhula pyrrhula
Abstract:Each year over five years (1962?67), the ratio of first-year to adult Bullfinches netted in Wytham Woods, near Oxford, increased from July or August to October, then declined to a fairly constant level from January onwards. The first-year to adult ratio in October, used as a measure of annual productivity, varied from 2.8 to 5.5 in different years. A high first-year to adult ratio in October was followed by a relatively high ratio throughout the next year and beyond (excluding the new juveniles that appeared among netted birds from July).Each year over five years (1962?67), the ratio of first-year to adult Bullfinches netted in Wytham Woods, near Oxford, increased from July or August to October, then declined to a fairly constant level from January onwards. The first-year to adult ratio in October, used as a measure of annual productivity, varied from 2.8 to 5.5 in different years. A high first-year to adult ratio in October was followed by a relatively high ratio throughout the next year and beyond (excluding the new juveniles that appeared among netted birds from July).
URL:http://www.tandfonline.com/doi/abs/10.1080/00063659909461146
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith