AVIS-IBIS

Birds of Indian Subcontinent

Aging and Sexing Common Snipe Using Discriminant Analysis

Publication Type:Journal Article
Year of Publication:2000
Authors:McCloskey, JT, Thompson, JE
Journal:The Journal of Wildlife Management
Volume:64
Issue:4
Date Published:2000
ISBN Number:0022541X
Keywords:Gallinago, Gallinago delicata, Gallinago gallinago, Scolopacidae
Abstract:Common snipe (Gallinago gallinago delicata) harvest surveys and banding programs have been hampered by the inability to externally distinguish between age and sex cohorts. We measured 11 skeletal and 34 plumage characteristics on 152 male and 220 female snipe that had been internally sexed. We also compared coloration of plumage and soft parts between 131 hatch-year (HY) and 93 after-hatch-year (AHY) snipe that were aged internally using presence or absence of the bursa of Fabricius. Using discriminant analysis of morphological characteristics, we developed 5 discriminant models to sex common snipe. Discriminant equations for sexing common snipe contained 1-4 variables and were tested using cross-validation (i.e., jacknifing) and an independent sample of 99 birds. Common snipe could be correctly sexed 73-91% of the time, depending on the model. To facilitate a parts-collection survey to determine sex ratio in the harvest, we derived 3 discriminant models using strictly feather measurements. After-hatch-year and HY common snipe showed no consistent differences in plumage and soft part coloration. However, once snipe were sexed, they could be aged using 1 of 4 discriminant functions that aged snipe with 77.5-84.1% accuracy. These aging and sexing techniques will be useful in monitoring snipe populations, establishing harvest surveys, and conducting future research on common snipe.
URL:http://www.jstor.org/stable/3803205
Short Title:The Journal of Wildlife Management
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith