Wednesday, March 25, 2009

April Phenology

Nature Watch
March 25, 2009

By Susan Benson,CNHM Director of Education

The robins have returned! Museum members and Sawyer County Record readers have reported observations of having seen them Monday, March 16 (in Barnes) and Wednesday, March 11 (in Cable and Hayward.) Trumpeter swans were observed on Mosquito Brook Road on Tuesday, March 17. An American kestrel was observed in Ashland on Monday, March 16. Other observations of mergansers and mallards have filtered into the Museum. A flock of common loons was seen on Thursday, March 18 in Seeley. A first chipmunk was also reported to have been seen in Hayward early in the week. Spring is finally here, and April will bring along with it plenty of spring activities. Just how fast does spring move, and what can we have to look forward to seeing during the upcoming weeks?

March 20, dubbed as the first day of spring, is not the only indicator that spring has sprung. In the early part of the 20th century, an entomologist named Andrew Delmar Hopkins tried to describe the relationship of elevation, latitude and longitude to the coming of spring. Roughly speaking, Hopkins’ Law of Bioclimatics calculates that spring moves northward by about twelve miles per day. Elevation and longitude also factor in, predicting spring’s later arrival at higher elevations and westward longitudes. However spring travels, we are happy to see it arrive!

Bird migration is in full swing by April. During a typical spring, waterfowl and black bird species are usually the first birds back in large numbers. By late April, birdwatchers should be seeing new species just about every day. Some of the birds are seeking out nesting and breeding territories, while others are stopping to eat for a few days before continuing their northward journey.

Common loons should continue arriving in the north during April. These birds have been spending the winter along the Atlantic coast, but by mid- to end-March they will have ventured north of the Carolinas to begin their inland flight. During this flight loons need to follow rivers and lakes because they can’t land on anything other than water. The Great Lakes can also aid loon migration. The Great Lakes usually open up before our surrounding northern lakes, and loons gather on the Great Lakes, making frequent flights to search for open water. Consequently, a pair of loons might land on "their" lake minutes after the ice disappears because of these flights. The Great Lakes provide loons with a distinct advantage by offering them “first dibs” at choosing their preferred nesting habitat. Keep your eyes out as this bird flies overhead, presumably on their way to the great Lake Superior.

A few more signs of spring to watch for in April: spring peepers chirping, grouse drumming, bloodroot blooming, dandelions blooming, and ticks and mosquitoes biting. We want to hear about your phenological observations! Send your seasonal sightings to the Cable Natural History Museum through Email at Please include information on the specific date and place in which you observed the natural sighting.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 13470 County Highway M or on the web at to learn more about exhibits and programs.

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