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This is a multi-part message in MIME format. --Boundary_(ID_69ee7O7+N+IsvtP1I+a5DA) Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT 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 --Boundary_(ID_69ee7O7+N+IsvtP1I+a5DA) Content-type: text/html; charset=iso-8859-1 Content-transfer-encoding: 7BIT <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2900.3132" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial size=2>Hi, all-</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Here's a question that I ponder from time to time: Why do male hummingbirds wait around here all summer before migrating south?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>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. </FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Why don't they just go back south once the females are sitting on nests?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>I can think of a few not-very-convincing reasons:</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>- The environment here (food, shelter, weather, predation pressure) might be better than on their southern range</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>- Some resources that they need on migration are not yet ready (e.g. some important flowers not generating nectar yet)</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>- There's always a chance that an un-mated female will turn up (I call this the "wishful thinking" hypothesis)</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Any other thoughts?</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>Peter Payzant</FONT></DIV> <DIV><FONT face=Arial size=2>Waverley</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML> --Boundary_(ID_69ee7O7+N+IsvtP1I+a5DA)--
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