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  • What happened to this Cooper’s Hawk egg?

    Question

    Today April 15 I found a coopers hawk egg in my front yard under a nest that the hawks have used the past 2 or 3 years. It had a pecked hole in it and a reeky odor. When do these eggs typically hatch or was it predated? I ID'ed the egg from an internet picture which looked exactly like the egg I found. Thanks in advance for info you can give me about the egg.

    Naturalist's Response

    It’s hard to know what happened with the Cooper’s Hawk egg. Hatch dates depend on when the last egg was laid and how long the incubation period is. For Cooper’s Hawks, here the nesting information from Cornell’s All About Birds site:

    NESTING FACTS

    Clutch Size: 2-6 eggs
    Number of Broods: 1 brood
    Egg Length: 1.7-2.0 in (4.4-5.1 cm)
    Egg Width: 1.4-1.6 in (3.5-4 cm)
    Incubation Period: 30-36 days
    Nestling Period: 27-34 days
    Egg Description: Pale blue to bluish white.
    Condition at Hatching: Covered in white down and weighing just 28 grams or 1 ounce, but able to crawl around nest.
    So, it depends on when the female starts incubating. If the adults are actively feeding young in the nest right now, then maybe that egg did not hatch —or started to hatch and the nestling could not get out. Some birds remove eggs that don’t hatch from the nest. Or perhaps something pecked the egg after it fell out. I’m sorry not to have a better answer.
     
    -Naturalist Linda Gilbert