In recent years, several birders have expressed opinions that birds seem to be arriving earlier in spring migration than years ago. It seemed to me this was indeed the case, but impressions are not facts. In an effort to put to rest my own impressions and perhaps that of others, I decided to do an analysis of the timing of migration based on records that I have been keeping since 1974.
Author: Robert A. Duncan
Volume Number: 40 Year Published: 1993
Issue Number: 2
Page Number: 7
Link to article: http://birdlife.aosbirds.org/1993/Vol. 40 No 2 1993_p7-8.pdf
Link to the full issue of BirdLife: http://birdlife.aosbirds.org/1993/Vol. 40 No 2 1993.pdf