Date: Sun, 28 Apr 2002 12:31:49 -0400 Reply-To: Maryland Birds & Birding Sender: Maryland Birds & Birding From: rob gibbs Subject: Re: RFI: Canada Goose clutch size MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit We've been doing a lot of Canada goose egg oiling in Montgomery County and therefore looking at a lot of nests. The average number of eggs seems to be about 6 but higher numbers are not uncommon. We have seen examples of egg dumping or dump nesting especially where large numbers of geese are nesting close together (we have one island in Lake Needwood about an acre in size that has over 100 nests each year). We had 18 eggs in a single nest at this location last year and last week had 22 eggs in a nest. I doubt that this many eggs can be effectively incubated so most will likely not hatch. Some of the eggs were damaged as if by a predator and at least one had rolled out of the nest so it could be that this nest had been abandoned by the parents and was just being used as a dump site by other geese. I was not present last week when the oiling was done so I don't know if the eggs were warm (we use a border collie to clear the island of geese so we don't have to fight our way from nest to nest therefore the only way we can tell if a nest is active is to see if the eggs are warm)- I will ask about this. Rob Gibbs M-NCPPC Montgomery County Parks Walter Ellison wrote: >There is a phenomenon in waterfowl and some other waterbirds often termed >"adoption" or more awkwardly "brood amalgamation". On occasion young ducks >join a brood from which they didn't hatch. Hens don't seem to discriminate >against the newcomers. Given biparental care in geese and swans it's >probably less common among those fowl than ducks, but it seems more likely >in your case than a 13 egg clutch. Another possibility is the addition of >eggs to the clutch by unrelated female geese in your brood mother's nest, >something called dump nesting by waterfowl biologists, also unlikely with a >vigilant father nearby, but possible nonetheless. > >Just some ideas, > >Walter Ellison >MD/DC Atlas Coordinator/MOS >23460 Clarissa Rd >Chestertown, MD 21620 >rossgull@crosslink.net > >======================================================================= >To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com >with the following message in line 1: signoff mdosprey >======================================================================= > ======================================================================= To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com with the following message in line 1: signoff mdosprey ======================================================================= =========================================================================