A couple weeks ago Bob Nelson asked a goose question I've wondered about for several years. The Crystal Lake man wanted to know if Canada geese reshuffle their broods.
His question gave me the impetus to find the answers.
Here's at least four broods of geese packed together like a preschool for goslings on our town pond Saturday morning.
Nelson first e-mailed earlier this month:
``[W]hile walking the dog, I noticed 2 new Canada goose families on a small pond in the park behind my house. Each pair of adults had 3 very small babies. [The following morning] I noticed one pair had 5 babies and the other, one. [Two days later] all 6 babies were with one pair of the adults (3 other adult pairs were present, all without broods).
This pond is relatively isolated so I am sure that the families are not moving between different ponds. I have never heard of this reshuffling of broods before. Is this common?''
The first extended response came from Graham Smith, a west suburban man who hikes all over the area on a weekly basis.
``I have often seen expanding groups of goslings with a pair of geese after initial leaving of the nest. In some cases it seems like there is baby-sitting while parents are gone, but more often, the goslings seem to be abandoned by their parents and adopted by another pair.
This doesn't seem well understood, but I could guess from an evolution perspective that the parents that abandon their goslings have a better chance of surviving themselves and the adoptive parents real goslings have a better chance of survival in a larger flock of goslings. Maybe first time parents abandon their goslings to older experienced parents - just a guess.
A great book about goose behavior is The Geese of Beaver Bog by Bernd Heinrich.''
State waterfowl biologist Ray Marshalla knew ``that they form gang broods but didn't know if they go back and forth as described.''
So he asked a couple other biologists.
Marshalla e-mailed, ``Dan Holm said that reshuffling is very common among goslings, especially when they are less than 2 weeks old. As Roy mentioned below they also travel long distances from water and it could be other broods they are seeing as well.''
Marshall was referring to this from urban waterfowler project manager Roy Domazlicky:
``I have heard of reshuffling like this. Even though they are `sure' that other broods are not walking in it is very difficult to count that out because they will travel a lot with those broods. I believe the literature says up to 5 miles.''
Last week, Nelson sent an update:
``This morning a new brood on the pond with 4 very small goslings. At the other end of the pond, last week's group now has 7 babies with one noticeably smaller than the rest. Looks like we have a serial gosling-napping pair. I'm wondering if it is because the pond is small and the families are too close together.''