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to keep feeder Hi Peter Migration has lots of interesting questions attached to it. Why do male black duck go to Labrador in the summer whereas male mallards stay here? Where do all our robins go after breeding season only to reappear latter? Why do wood ducks that nest in the south appear in NS in the fall? A plentiful area for study. Enjoy the summer - don't tax your brain too much! Paul --- Peter Payzant <pce@accesswave.ca> wrote: > Hi, all- > > Here's a question that I ponder from time to time: > Why do male hummingbirds wait around here all summer > before migrating south? > > Once they've mated with a female, their purpose here > is essentially over. They don't help in taking care > of the young, and there's only one brood per female > per year. In fact, you could say that the males > create a negative reproductive pressure by competing > with the females and young for food. > > Why don't they just go back south once the females > are sitting on nests? > > I can think of a few not-very-convincing reasons: > > - The environment here (food, shelter, weather, > predation pressure) might be better than on their > southern range > > - Some resources that they need on migration are not > yet ready (e.g. some important flowers not > generating nectar yet) > > - There's always a chance that an un-mated female > will turn up (I call this the "wishful thinking" > hypothesis) > > Any other thoughts? > > Peter Payzant > Waverley > > ____________________________________________________________________________________ Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/features_spam.html
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