Migration of Blue Jays in Eastern North America

Jays in eastern North America and to make comparisons of the movements of these birds in eastern North America with those west of the 100th meridian.Methods From the Bird Banding Laboratory, U.S. Fish and Wildlife Service, I obtained a print-out of banding and recapture records of Blue Jays banded in the Atlantic Flyway of the eastern United States and the Canadian provinces east of and including Ontario.For my analysis, Florida, Massachusetts, New Jersey, and New York were chosen as states with the largest numbers of records and representing different parts of the Blue Jay's range.The print-out sheets were hand-searched for records addressing obvious questions and for information to develop new questions which could be addressed.Based chiefly on information gleaned from the banding and recapture records, the records were classified according to the time the birds could be expected to be on their breeding grounds, on their wintering grounds, or in migration between these two locations.Records of previously banded birds that were captured and released at the same place by the original banders (Banding Laboratory code 99) were separated from those otherwise recaptured, to avoid exaggeration of the number of birds shown not moving.It must be noted also that records of birds banded as locals (birds too young to be capable of sustained flight) define the end of the nesting period for the birds involved, and backward adjustment by the appropriate amount must be made to determine other stages of nesting activity.A word of caution must also be introduced here to warn the reader to remember that, because of differences in sizes of states, the numbers of birds recovered in different states represent different values.I think, however, that these values are exact enough that their comparison can be expected to reveal existing patterns in migratory behavior and thus to justify mapping the recoveries by states. ResultsThis analysis made use of data from 8,002 recaptures from 101,903 banded Blue Jays.Of the 8,002 recaptures, 4,861 were of birds recaptured and released by the bantiers, leaving 3,141 birds recovered other than by the original bantiers, with a recovery rate of 3.1% (Table 1).A tabulation for banding of locals by months showed Blue Jays in New Jersey near their hatching places from May to September, with peak numbers in June and July (Table 2).In New York, birds were banded as locals from May to August --peak numbers also Table 1.Number of Blue Jays banded and number recaptured Number recaptured Percent recaptured Where Number Number other than being of birds not banded banded recaptured captured & released captured & released Florida 13,259 1,057 642 4.8 Massachusetts 23,986 2,277 783 3.3 New Jersey 36,944 3,107 1,094 3.0 New York 27,714 1,561 622 2.2 Total/average

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.