20-14-7

All three nest boxes were occupied at about 2:00pm on Friday. Here’s a link to the camera page.

As of Friday there were more eggs in each nest box vs. when I last checked on Monday:

  • 20 eggs in the East nest – 5 more than on Monday
  • 14 wood duck eggs in the West nest – 2 more
  • 7 hooded merganser eggs in the South nest – 3 more

The hooded merganser is laying one egg every 2 days. They are larger, whiter, and more round than wood duck eggs.

The hooded merganser is usually in the nest box for about 90 minutes each time. She’ll start incubation in the next week or so. Wood ducks have visited the South nest briefly but have not left any eggs so far.

The new eggs in the East and West nests have been provided by other wood ducks because the incubating duck was all done laying when incubation started. Both wood ducks and hooded mergansers lay eggs in multiple nests. The biologist’s term for this is “dumping”. Here is more information about it. Dumping is partly a way for a duck to improve the chance that her offspring might survive even if something happens to her: fox, coyote, eagle, bird flu, etc. It also can be due to a shortage of nesting sites. However it works only for eggs deposited before incubation begins because eggs added more recently will not develop in time to hatch with the others – the duck family leaves the nest the day after hatching and they never return.

Sometimes dumping that happens after the start of incubation will occur when the incubating duck is out getting food but frequently there will be 2 ducks in the nest box together. Once in a while this is peaceful (see this video) but often there is a scuffle (as in this video) where the resident tries to repel the invader. If the invading duck leaves an egg the incubating duck will always follow her instinct to add it into the clutch and incubate it with the others. One duck does all of the incubating and then for about 2 months she takes care of all the ducklings that hatch: her own, those of other ducks, and sometimes a mix of wood duck and hooded merganser ducklings.

One thought on “20-14-7”

  1. Paul,
    I really appreciate the enhancement to see the 4 cameras together. It will be especially helpful on jump days!
    Thanks.

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