While we are waiting (?patiently?) for spring to really get rolling! here are a few things to think about.
- Sexual dimorphism in bird plumage: Among all the thousands of bird species there are many in which males have brighter! flashier breeding plumage than the females. Think of cardinals! some warblers! orioles! for example. Many of these colorful males share at least some of the parental duties. In some cases! however! males have quite extravagant plumage: for example! peacocks! wild turkeys! many kinds of pheasants! cocks-of-the-rock! and so on. The usual explanation is that intense competition among the males for territories and female favors has led to the very fancy plumage! and the males do little or no parental care. Or! conversely! the males did so little parental care that they were free to spend their time in competitive interactions! leading to the evolution of showy plumage. For some of those species! the precocial state of the chicks (quickly able to leave the nest! run around! and regulate their own body temperature) perhaps reduced the need for two guarding parents! freeing up the males. But that suggestion does not apply to the cocks-of-the-rock! in which both country wise email marketing list parents are reported to tend the nest.
The reverse is the case in some other species!
although it is relatively rare: females have somewhat more colorful plumage than the males: for example! phalaropes! painted snipes of the Old World! Eurasian dotterels. In these species! the usual parental roles are reversed: the males do the parental care and females often compete for males’ attention. That might free the females to become flamboyant! but they are just a little more colorful than the males. So that raises a question: Why don’t these females develop flamboyant plumages? Are the levels of competition for mates and territories too low to require fancy plumage? Or is it just a matter of chance! the right mutations! and a small sample size?
To complicate simplistic kinds of explanations! there are
several other species that have the parental role reversal but without notable plumage difference (e.g. African black coucal! kiwi) or they have significant plumage differences and no role reversal (Eclectus parrots! with bright red females and green males). Similarly! it’s the female of our local belted kingfisher that wears the rusty band on the upper belly! and both sexes tend the nestlings. Explanation of these varied examples clearly requires more information than patterns of parental care and three observations to ponder intense competition for mates. There must be multiple factor involved in the evolution of plumage dimorphism.
- You may have noticed that along the roadsides! in winter and early spring there are shrubs with red twigs. Those are blueberry bushes! but I have not determined which species. In contrast! under the tree canopy! blueberry twigs are usually brownish. In the same genus (Vaccinium)! the red huckleberry twigs are quite green. Why should the blueberry bushes that have some exposure to the sky bear red twigs? Internet sources suggest a disease! but I am dubious. Anthocyanins often make b2b fax lead red colors in plants and may provide some form of protection from UV rays or cold temperatures. They are known to do so in other situations! but do roadside conditions make such protection advantageous? And why are those twigs especially sensitive to those conditions?