Peregrine Falcon Field Notes-May 7, 2007, The Raptor Center at the University of Minnesota

By Jackie Fallon

May 10, 2007

The eggs have hatched!

The results of the breeding season are starting to come in. When peregrines lay eggs, you cannot always assume that they will hatch, reach banding age, or survive to fledging age. We are at the first step though in the process of sites where we know the adults have laid eggs.

Peregrines incubate their eggs for approximately 33-35 days after they lay their second to last egg. Most of the sites where we can actually count eggs have four eggs in the box or tray; the City Center site in Minneapolis has five eggs!

During incubation, the observation part of my job is fairly relaxed. Just sit back, count to 33, and then hope that you see a change in the behavior of the adults to tell you that the eggs have actually hatched. For the first week after hatching, the young chicks need to be protected from the weather (heat, rain, snow, cold) by the adults. This behavior is called brooding. Some of the pairs of adults on territory are starting to brood their newly hatched chicks.

We estimate that our first hatching occurred the first week of May in Sartell and Minneapolis at the Lock and Dam 1 site, with many more of the sites hatching this week. At other sites, we will know exactly when the eggs hatch because there is a remote camera on the nest box or tray. These sites include the Mayo clinic in Rochester, the Colonnade building in Golden Valley, Bank of the West in Fargo, North Dakota, and the City Center Tower in Minneapolis. You can watch the City Center site for yourself at www.thefalconsat33.com and the Bank of the West in Fargo at http://www.prairiepublic.org/ features/riverwatch/project_falcon/ webcam-small.html.

The female at the City Center site in downtown Minneapolis

The camera allows for a very close and exciting view into the lives of the peregrine falcon. You can count the eggs in the box, watch the eggs hatch, observe the adult peregrine feed their newly hatched chick, or watch the new chick sleep.

The next step in the peregrine project will be determining the date where we will band the young chicks. We try to band the chicks at 18-25 days of age, preferably about 21 days. If they are any younger than 18 days, it becomes difficult to determine their sex and therefore determine which size band to put on their leg. If they are much older than 25 days, they are more active and could jump from the box, tray, or cliff. I have a pretty good idea on hatching and banding date for the majority of the sites, and am trying to finish this work next week when I travel to the North Shore of Lake Superior to get an idea on the successes of the 12 cliff sites we monitor.

Anyone who is interested in watching us band the young chicks is invited to come to any of the scheduled banding sessions in May and June. Things sometimes change, though, so check this list often to make sure the banding is still going to happen.

This is an exciting time for the field team and we are hoping you will continue to watch the birds with us.