Apr 22 2009


Published by at 3:56 pm under Peregrines

Peregrine falcon, Tasha, incubating eggs at Gulf Tower (photo from National Aviary webcam)

The lady bird in this picture is keeping a secret she won't tell any of us.  When will her eggs hatch? 

Based on our best guess we predicted they would hatch on or after April 19th because the normal incubation period for peregrine falcon eggs is 33-35 days.  What we guessed was that she started incubation after she laid her third egg.  Well, maybe she didn't start until her fourth egg so I got out my calculator and was going to tell you a new date - but I thought better of it.

I had my heart set on April 19th and was prepared to wait until April 20th, but now I'm getting really impatient.  The worst of it is that I got your hopes up too.  No way am I going to predict a new hatch date!

Sigh.  We'll just have to wait.

(photo from the National Aviary webcam at Gulf Tower, Pittsburgh)

2 responses so far

2 Responses to “When???”

  1. Jon 22 Apr 2009 at 4:50 pm

    Perhaps the fact that she laid a 5th egg 6 days after the 4th is throwing you calculations off. Is that unusual for there to be such a large gap between 2 eggs? Is the 5th egg less likely to hatch than the other 4 or if it does hatch, will it hatch several days after the others?

  2. Kate St. Johnon 22 Apr 2009 at 5:11 pm

    A fifth egg laid far after the others is not less likely to hatch but it’ll be the runt of the family. One year Tasha laid a fifth egg late and it hatched a couple of days later the rest. That nestling remained a few days behind her siblings in size, agility and maturity.

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