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Thread: Knock it off

  1. #1
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    Default Knock it off

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    Northern Rough-winged Swallows (Veterans Oasis Park at Chandler, Arizona)

    The youngster was very loudly demanding some food from the adult. It seems like the adult got a little annoyed at the noise and extended its wing toward the noisemaker. I'm not sure if the wing extension was to comfort the young bird or was to politely ask the young one to be quiet.

    I don't see much interaction between birds and hope you like this behavior shot

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    I do like it Scott, and it (likely) illustrates the interesting concept of "parent-offspring conflict". Essentially this is that in evolutionary terms, the interests of offspring aren't always the same as parents, and conflict arrises as a result. For most of the development period of young, there is no or little conflict- evolution favours parents that provide good care to their offspring, and evolution favours young who do all the things young do: beg for food and take food from their parents (at least for young that don't feed themselves), snuggle under the parent for warmth and shelter etc etc. However, parents of most bird species might expect to live long enough to produce another brood either in the same year or future years so it is in their interest to cut off care to the current brood to "save" themselves for the next. This is when the conflict starts because evolution favours young who get the most out of their parents, not young who spare their parents for the next brood. Conflict is often manifest in persistent begging from the young but no reaction or avoidance on the part of parents. A classic case of this is with some penguin species whose young literally chase their parents around the colony in an attempt to get some food.

    This final finishing phase in seabirds is very important because often the chicks are heavier than the adults and need to lose wight, and need to learn to find food for themselves. Withholding food on the part parents accomplishes these goals and as mentioned, saves the parents for their next brood.
    Last edited by John Chardine; 05-31-2009 at 02:40 PM.

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