Golden-winged Warblers by Emily Rondel

Wednesday, April 5, 2017 7:30 p.m. at the Orillia Museum of Art and History

Topic: “A golden Opportunist?: the Golden-winged Warbler in Ontario”

At the recent meeting of the Orillia Naturalist Club guest Emily Rondel, currently Toronto Project Coordinator
of Bird Studies Canada, spoke to the members about her research into the life of the Golden-winged Warbler.

Emily has been studying the Golden-winged Warbler and its hybridization with the Blue-winged Warbler for the past six years.
The Golden-winged Warbler is one of North America’s most rapidly declining song birds and hybridization
with the Blue-winged Warbler seems to be its biggest threat. Another reason for the decline is the large changes
in habitat across its range, which differ between central and southern Ontario. However, while the decline has been
79 per cent over the last 20 years, it does not seem to be occurring in all of the Golden-wing’s range.
There are three breeding populations in Ontario and 85 per cent of the species breeds in the Great Lakes area.

At the end of the summer the warblers migrate to the southern part of Central America and the northern area of South America.
However, the three breeding groups do not seem to winter together.

The warbler uses a dynamic forest habitat but builds its nest on the ground in open areas among dense vegetation.
There are 4 to 6 eggs and hatching takes place between 7 to 9 days. Once the chicks are fledged, Golden-wing families
seem to rely on both mature forest habitats and scrubby habitats for food sources.

In the 1950’s the Golden Wing expanded from the north shore of Lake Erie where it doesn’t live anymore.
By the 1990’s the warbler was up as far as North Bay and it is now as far west as the Manitoba border.

Cross breeding with the Blue-winged Warbler has resulted in two other hybrid forms: the Brewster’s Warbler,
discovered by William Brewster, and the Lawrence’s Warbler. The Brewster’s is the more common hybrid, showing
a lot of the dominant characteristics of the birds, while the Lawrence’s Warbler form shows more recessive characters.

The hybridization levels between the Golden-wingand Blue-wing has been determined by blood tests and
a study of the DNA of the matriline. Although this DNA evidence supports the idea that these birds are different
enough genetically to be separate species, other molecular work has shown that the species barely differ at all.
There is no consensus as to whether the birds are two closely-related species or one species with a lot of internal variation.
It is Emily’s opinion that the Golden-winged and the Blue-winged Warbler are the same species.

Photos from Dianne Stinnissen.   Text from Murray Binsted

Leave a Reply

Your email address will not be published. Required fields are marked *