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First Evidence For A Second Breeding Season Among Migratory Songbirds (1 Viewer)
- Thread starter Dimitris
- Start date
Colin
Axeman (Retired)
Two obvious questions to my mind. 1. Why has this not been noticed before? (maybe it is a new happening) and 2. Will other species start to do this if it is a new occurrence? And a 3rd question, if it is a new happening, what has changed for this to occur? Just a few thoughts.
timwootton
Well-known member
Rohwer suggests that this is 'traditional' behaviour - the second breeding cycle (in Y-b Cuckoo) being critical to maintaining the overall population:
''Then there is the yellow-billed cuckoo, once commonly seen throughout the western United States and as far north as the Seattle area but now seldom seen along the West Coast. Disappearing habitat in the U.S. is usually cited as the reason.
But Rohwer believes the real problem could be the transformation of thorn forests of southern Sonora and Sinaloa, states in northwestern Mexico, into irrigated industrial farms. That loss of habitat, he said, could mean not enough young are produced in the second breeding season to sustain the populations previously seen on the U.S. West Coast.''
. . . and he goes on to suggest that the reason this behaviour hasn't been documented before could be due to the inhospitable environment in the thorn forests:
'However, with plenty of biting insects, temperatures often at 100 degrees Fahrenheit and humidity hovering near 100 percent, it is a difficult place for researchers to work, so there has been little previous documentation of life in the thorn forest. The new findings could spur more work there.''
''Then there is the yellow-billed cuckoo, once commonly seen throughout the western United States and as far north as the Seattle area but now seldom seen along the West Coast. Disappearing habitat in the U.S. is usually cited as the reason.
But Rohwer believes the real problem could be the transformation of thorn forests of southern Sonora and Sinaloa, states in northwestern Mexico, into irrigated industrial farms. That loss of habitat, he said, could mean not enough young are produced in the second breeding season to sustain the populations previously seen on the U.S. West Coast.''
. . . and he goes on to suggest that the reason this behaviour hasn't been documented before could be due to the inhospitable environment in the thorn forests:
'However, with plenty of biting insects, temperatures often at 100 degrees Fahrenheit and humidity hovering near 100 percent, it is a difficult place for researchers to work, so there has been little previous documentation of life in the thorn forest. The new findings could spur more work there.''
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