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Posted by Alex Harper on 13:50:29 04/18/11
In Reply to: Re: Migrants Few & Far Between in Collier County posted by Toe
Denial that this is the worst spring migration most of us can remember? It is the worst I can recall in my ten years of birding.
Denial that a massive, inexplicable die-off across the board occurred sometime within the past four to six years, yes I would deny that. Most, if not all, species are declining annually, but the rate you have suggested is not seen in nature outside of a petri dish. Bird populations are closely monitored, and if tens of billions (conservatively?) of Neotropical migrants were to simply vanish, the scientific community would notice. A look at breeding surveys later this year would likely reflect this.
Bird migration is too dynamic to expect the same results year after year. Way too many stochastic inputs and outputs to consider.
I have noticed that this April has been very dry. This has a lot to do with our numbers. Last April the Pensacola area was very wet and the numbers and species richness reflected the rain. If you consider that a passerine can fly 700+ miles in a single shot, why would it fly from southernmost Cuba to A.D. Barnes, which is less than 300 miles? We all know that precipitation equals birds the next day, but it plays a higher role then we think.
Here is an excerpt from Bob Duncan's book "Bird Migration Weather and Fallout (1992):
Year: 1976 Rainfall: 2.46" Comments: Dissapointing
Year: 1977 Rainfall: 2.24" Comments: Poorest April migration in memory
Year: 1979 Rainfall: 5.94" Comments: Best fallout in years (end of the month)
Year: 1980 Rainfall: 9.94" Comments: Outstanding
Year: 1981 Rainfall: 0.28" Comments: Very poor
Year: 1985 Rainfall: 2.19" Comments: One of the poorest.
Year: 1990 Rainfall: 4.54" Comments: Good birding
Year: 1991 Rainfall: 7.66" Comments: Great birding 19th to 30th
End excerpt.
I have been frustrated too, especially after reading of some of the 20+ warbler days along the Louisiana and Texas coasts. But it is what it is this year, and we should be sure of what it is not (i.e. anything to do with Richard Nixon!)
Most respectfully and best regards,
Alex
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