[CT Birds] Alder Flycatcher and Breeding Bird Evidence
ls.broker at cox.net
Fri Jun 1 17:38:27 EDT 2012
With hope and a major commitment in time, Connecticut soon will gear up to conduct its second Breeding Bird Atlas as a follow-up to its first statewide breeding bird atlas conducted in the mid-1980s. The timetable and strategy for such a Connecticut breeding bird atlas are under discussion within the state's major ornithological organizations.
This past year, Massachusetts completed the field work for its Mass Breeding Bird Atlas 2, held from 2007 through 2011. Massachusetts Commonwealth was divided into 1055 atlas blocks based on USGS topographic maps, and these blocks were surveyed by atlas volunteers for evidence of avian breeding during the five-year period. The data for Mass BBA2 are available on-line at www.massaudubon.org/bba2/. At this website, one can view the breeding bird codes used in Massachusetts for the atlas. The evidence for breeding in Mass BBA2 ranges from Observed [present but no evidence of breeding] to Possible Breeder to Probable Breeder to Confirmed Breeder. There were seven different ways that a field observer could establish a species as a Probable Breeder. They included finding a male/female pair, singing seven days or more apart, on permanent territory, agitated behavior or anxiety calls, courtship behavior of copulation, visiting a probable nest site. (See the website for specific articulation of these breeding codes.) The key aspect of these evidences of probable breeding was that the observation had to be made during so-called Safe Dates established for each bird species based on knowledge of their life history patterns within the state.
Confirmed Breeder status in a given atlas block was achieved in any of 13 different ways, and this evidence included occupied nest, carrying nest material, nest building, physiological evidence (used by banders); distraction display (select species), unoccupied nest, precocial young, fledged young, carrying food, feeding young, carrying fecal sac, nest with eggs, and nest with young. (Again, see the website for a full description of these breeding codes.)
In the case of Alder Flycatcher, the established safe dates were from June 5 through August 1. Any date that Alder Flycatcher was observed in Massachusetts prior to June 5 was recorded as Observed and did not qualify for a higher ranking. The exception to this standard was if some category of Confirmed Breeder was recorded prior to the start (or end) of safe dates. So, in this example, if an Alder Flycatcher was heard singing on June 5 and again on June 12, it achieved the status of Probable Breeder PR(S). The species would not be 'upgraded' to Confirmed Breeder unless one of the evidences listed above for confirmation of breeding was observed in the field.
There's lots more that one can learn about breeding bird surveys by going to the website listed above. Mass Audubon published a "State of the Birds 2011: Documenting Changes in Massachusetts' Birdlife" report based on the first four years of the atlas, and the report is accompanied by a website, www.massaudubon.org/StateoftheBirds. Further analysis of the five years of field data continues.
I spent a major portion of the last three spring/summer seasons doing field work for MassBBA2 on Outer Cape Cod, and I now find my birding here less purposeful now that the atlas field work is completed. Connecticut, step up to the plate!
Steve Broker (Cheshire, CT and Wellfleet, MA)
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