Subject: [Tweeters] Another word about "White-cheeked Geese"
Date: Nov 5 13:10:02 2006
From: SGMlod at aol.com - SGMlod at aol.com


Greetings All

So, just another little bit about Canada/Cackling Geese.
The split was based on mtDNA differences, which is inherited from the mother
only. Among extant races --

Lesser (parvipes), Dusky (occidentalis), Vancouver (fulva), Great Basin
(moffitti), Greater (maxima) are the races of Canada that have occurred in WA.

Aleutian (leucopariea), Cackling (minima), Taverner's (taverneri), and
probably Richardson's (hutchinsii) are the races of Cackling that have occurred in
WA.

Since the taxa are pretty strongly female philopatric (females return to site
of birth faithfully; males pair with them during winter and go to their mates
natal site) hybridization tends not to show up in the mtDNA.

So, a breeding population of geese might have quite a few males of "the
wrong" taxa breeding in the colony, and one would not detect it in the offspring's
mtDNA.

There is some evidence that there is breeding between Lesser Canada
(parvipes) and both Taverner's and Richardson's Cackling Geese. There is also some
evidence that Dusky Canada (occidentalis) and Taverner's Cackling interbreed.
Bill Tweit and I saw a couple very bronzy birds that otherwise looked like
Taverner's at Nisqually last winter. One wonders if there was some occidentalis
genes in there.

Just to make life even more confusing.

Cheers
Steve Mlodinow
Everett WA