Supposed Periodicity of Redpoll, Carduelis sp., Winter Visitations in Atlantic Canada

Auteurs-es

  • Anthony J. Erskine 16 Richardson Street, Sackville, New Brunswick E4L 4H6
  • Reid McManus 657 Royal Road, Memramcook, New Brunswick E4K 1X1

DOI :

https://doi.org/10.22621/cfn.v117i4.831

Mots-clés :

Common Redpoll, Carduelis flammea, Atlantic Provinces, winter, irruptions, periodicity, food availability

Résumé

Redpoll (primarily Carduelis flammea) data from the New Brunswick–Nova Scotia border region were reviewed in the context of alleged biennial periodicity of irruptions south of their breeding range. Long-term records by the authors suggested a number of departures from visitation in alternate years. Three local Christmas Bird Counts (CBCs) spanning the last 41 winters supported the less-than-regular pattern shown by individual observations. CBC redpoll data from across the Atlantic Provinces revealed annual redpoll visitations across southern New Brunswick, where the largest regional counts (adjusted for observer effort) usually occurred. Visitation to Prince Edward Island, Nova Scotia, and Newfoundland was less frequent, and patterns there were often obscured by scarcity of CBCs with both long-run coverage and redpolls. Examination of those data in relation to varying food availability suggested that irregular abundance but near-annual occurrence of redpoll visitation explains observed observations better than attempts to find periodicity in their irruptions.

Téléchargements

Numéro

Rubrique

Articles