May 26 2014

Proof Of Nesting

Published by at 7:20 am under Bird Behavior,Nesting & Courtship

Ovenbird with nesting material, May 2014 (photo by Marcy Cunkelman)

The fact that it’s carrying dead grass tells us three things about this ovenbird:

  • It’s building a nest nearby,
  • It has a mate,
  • It’s female.

Back in 2004-2009 I participated in the second Pennsylvania Breeding Bird Atlas project in which we watched bird behavior and noted signs of breeding.   We learned that a bird is probably breeding if it’s holding territory, courting, or becoming agitated as we approach.  Its breeding is confirmed if the nest has eggs or young, or if we see an adult carrying food.  (Did you know that most birds don’t bother to carry food unless they’re feeding young? *)   The project was eye-opening because it forced us birders to slow down and observe what the birds are doing.

This ovenbird’s behavior — “Carrying Nest material (CN)” — is Confirmed or Probable nesting depending on the situation.  It’s true that an ovenbird carrying nesting material is a female and she already has a mate, but this is not true of all species.  In some, both sexes build the nest.  In others, such as the Carolina wren, the males build several “test” nests and the females choose.

Among ovenbirds only the female builds the nest and she doesn’t bother to do it unless she has a mate.  She chooses a depression of leaves on the ground and constructs a nest shaped like a beehive oven using grasses, plant fibers, weed stems, leaves, rootlets, mosses and bark.  When completed the nest is so well-hidden that it’s invisible from above.  Click here to see what the nest looks like with eggs inside.

Congratulations to Marcy Cunkelman on finding this ovenbird building a nest.  What a cool photograph.  I have never see this!

(photo by Marcy Cunkelman)

(* There are notable exceptions to the “carrying food” rule… worth learning.)

One response so far

One Response to “Proof Of Nesting”

  1. John Thomsonon 27 May 2014 at 3:44 pm

    What a cool house.

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