<\/a>A black-furred gray squirrel gleans spilled seeds below a bird feeder. ( Courtesy Photo \/ J. S. Willson)<\/p><\/div>\n\t\t\t\t
A string of bird-feeders and a water-bath outside a window offered continual entertainment, much more variety than at my Juneau house. A male cardinal sometimes claimed the water-bath for himself, but a female was never far away. There were red- bellied and downy woodpeckers, black-capped chickadees, house finches and goldfinches, a few house sparrows, bluejays (real ones, not our Steller’s jay), and white-breasted nuthatches. I always enjoy watching nuthatches scurry vertically up and down tree trunks. Walking down a tree trunk is made possible, it seems, by the large, strong hind toe on each foot, giving a good purchase on the bark. Best of all is watching a nuthatch fly to a trunk and instead of landing head-up, it turns in a flash and lands head-down. (Why don’t woodpeckers do that? They have two back toes on each foot, which would give a good grab on the bark.)<\/p>\n\t\t\t\t
Gray squirrels were occasional visitors to the spilled seed below the feeders, but they spent most of their time collecting hickory nuts and acorns. Gray squirrels occupy the eastern deciduous forests and are often found in wooded suburban areas. Bigger than our local red squirrels, they scatter-hoard their harvest, burying each prize separately; if they fail to retrieve their stash, the nuts may germinate and contribute to the forest composition.<\/p>\n\t\t\t\t
Mixed in with the normal gray-colored squirrels, we often see a few melanistic ones with black fur. The black fur results from a mutation in the DNA of a certain chromosome. If a black squirrel has two copies of the mutation, it is deep black, darker than one that has just one copy. If a blackish squirrel with one copy of the mutation mates with a normal gray squirrel, the litter generally has both blackish and gray pups.<\/p>\n\t\t\t\t
Is blackness an adaptation to some environmental condition? At present, there are two suggestions: It might contribute to concealment, especially in northern forests where there are more dark conifer trees mixed with the deciduous ones. Another suggestion deals with thermoregulation. Black squirrels are said to be uncommon in areas with high air temperatures. Research has shown that black squirrels have more cold-tolerance than the grays: they have lower heat loss at very low temperatures, as well as a lower metabolic rate and a better ability to generate heat. But it is not clear what, if anything, black fur has to do with all that. Things to ponder, but there seem to be no conclusive data, and other possible explanations may exist.<\/p>\n\t\t\t\t
• Mary F. Willson is a retired professor of ecology. “On the Trails” appears every Wednesday in the Juneau Empire.<\/em><\/p>\n\t\t\t","protected":false},"excerpt":{"rendered":"Observing the colors of the leaves…and squirrels. <\/p>\n","protected":false},"author":106,"featured_media":92509,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_stopmodifiedupdate":false,"_modified_date":"","wds_primary_category":11,"footnotes":""},"categories":[11,4],"tags":[],"yst_prominent_words":[],"class_list":["post-92508","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-home2","category-news"],"_links":{"self":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/92508","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/users\/106"}],"replies":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/comments?post=92508"}],"version-history":[{"count":0,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/92508\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/media\/92509"}],"wp:attachment":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/media?parent=92508"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/categories?post=92508"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/tags?post=92508"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/yst_prominent_words?post=92508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}