Hi, Tom -
I am aware of Bill Pranty's explanation and article, but I do not think the
Starling explanation accounts for the geographic patterns of the decline. Also,
Budgies are very slender and can fit into smaller nest holes than starlings.
Back in the late 1970s, in Oinellas County they seemed to be nesting quite a
bit in crevices in the eaves on buildings. Starlings were also abundant at that
time, and I am not aware that their population increased greatly.
I do agree with you about a wide variety of reasons for introduced species'
declines, and obviously the Starling explanation would apply mainly to
cavity-nesters, and not to birds like goldfinches or francolins.
Wayne
From: "Tom Crabtree" <tc@xxxxxxxxxx>
To: "whoffman" <whoffman@xxxxxxxx>
Cc: "baro@xxxxxxx" <baro@xxxxxxx>, "Jeff Gilligan" <jeffgilligan10@xxxxxxxxx>,
"Paul T. Sullivan" <paultsullivan@xxxxxxxxxxxx>, "obol" <obol@xxxxxxxxxxxxx>
Sent: Wednesday, March 18, 2020 3:36:10 PM
Subject: [obol] Re: eBird reports of European Goldfinches in USA
A lengthy article by Bill Pranty, of Audubon in Florida in 2001 indicated
that the main suspect of the Budgerigar decline in Florida was competition
for nest sites with House Sparrows, not disease. He also posits that the
decline in Mynas in the Vancouver area was due to competition with
Starlings. Another article posits that the decline in the Budgie population
followed a series of deep freezes in the 80s. With the large numbers of
introduced species around the country over the decades it is likely there
is a wide variety of reasons behind their eventual decline.
Tom Crabtree, Bend
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