The Wilson Bulletin
Book format: An electronic version of a printed book that can be read on a computer or handheld device designed specifically for this purpose.
Publisher: Date:8/5/2009 - General Books LLC
By: Wilson Ornithological Society
Excerpt from book: THE SPRING MIGRATION OF 1907 IN THE VICINITY OF CHICAGO. BY JOHN F. FERRY. The weather prevailing during March, April, and May of 1907, was so abnormal in character that the study of bird- migration during these months was one of absorbing interest to the ornithologist. March, 1907, was a very unusual month, it being the warmest on record for this vicinity, with one exception. Its mean temperature was 43, which made it actually average 3 degrees warmer than the following April. The average daily temperature was 7.6 degrees warmer than the normal temperature for this month. The month was humid, cloudy and inclement, there being nine days when there was hail, sleet, fog, or thunderstorms and during the month there were but three days of continuous sunshine. Notwithstanding these unfavorable elements bird-life was abnormally abundant from the 16th day on, from which day almost continuous warm weather prevailed. This indicates that temperature is a very important factor in influencing migration. April was quite the opposite of March, it being the coldest April on record with one exception. The mean temperature of the month was 40 as compared to a normal temperature of 46. The average daily temperature was Ql/2 degrees cooler than the normal. There were but seven clear days during the month. May was peculiar, it being the coolest May on record (one exception). Its average temperature was 52, while the normal temperature for May is 56. The corresponding influence of these peculiar weather conditions upon bird-migration was quite noticeable. The first half of March was cool, the temperature averging 35 up to the 16th, when the first movement of the year really began. During the remainder of the month the temperature averaged 50, and beginning with the large movement on the 1...