Hi John et al, this is well-known gallinule “parental” behavior. As many will know, birds often lay more eggs and hatch more young than they can rear. The theoretical explanation is that in a good year, when the healthiest as well as most young can be raised, parents benefit by being ready with that number in the nest. But food or conditions will be less than good in many years. Probably most such young die without direct parental actions, simply through feeding rules that favor larger chicks, or because smaller young run out of fat fuel sooner during lean patches and stop begging and die.
But gallinules (moorhens in Europe) are known for directly reducing the number of young, using a behavior “touseling” (yes, it even has a name) in which adults start to peck at and drive off/down select young. According to the literature, they are likely to select less brightly colored young. The color is related to the health and immune status of the chick, so they appear to be selecting the lower quality young. In some raptors, pelicans, boobies, and egrets, larger siblings are usually the ones to peck and often kill their smaller siblings. Anne Anne B Clark 147 Hile School Rd Freeville, NY 13068 607-222-0905 anneb.cl...@gmail.com > On Jul 6, 2017, at 7:32 AM, k...@empacc.net wrote: > > At the Van Dyne Spoor wetlands yesterday we observed what seemed vey unusual > gallinule behavior. An adult was swimming along up a small channel in the > surface weeds while three young were sort of lazing around nearby. A second > gallinule was a distance off. > > Suddenly, the adult accelerated and altered course toward one of the > youngsters. When they were close, the adult came up out of the water and > crash dived on top of the kid! The adult quickly surfaced and, despite > watching for some time, we never saw the young reappear. The other two kids > and the other adult ignored the whole affair. > > I hope the youngster just retreated underwater to heavy cover. > > John > > -- > John and Sue Gregoire > Field Ornithologists > Kestrel Haven Migration Observatory > 5373 Fitzgerald Rd > Burdett, NY 14818 > 42.443508000, -76.758202000 > -- > Cayugabirds-L List Info: > Welcome and Basics <http://www.northeastbirding.com/CayugabirdsWELCOME> > Rules and Information <http://www.northeastbirding.com/CayugabirdsRULES> > Subscribe, Configuration and Leave > <http://www.northeastbirding.com/CayugabirdsSubscribeConfigurationLeave.htm> > Archives: > The Mail Archive > <http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/Cayugabirds> > BirdingOnThe.Net <http://birdingonthe.net/mailinglists/CAYU.html> > Please submit your observations to eBird <http://ebird.org/content/ebird/>! > -- -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
