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 The first sign of the nesting season is upon the peregrine falcon in the Midwest, with the birds showing courtship behavior and preparing the nest site.
Historically, peregrine falcons nested on cliff faces and used the ledges high on the cliff. In these ledges, they would generally lean forward, putting weight on its breast and kicking backward with their feet, push and make what is called a scrape, or small indentation, where the eggs would be laid and incubated. Peregrines would also utilize abandoned osprey or raven nests. From the best available data, the Midwest peregrine population probably was around 40 pairs in pre-DDT times.
Today, the peregrine falcon has adapted to utilize a varied landscape that humans have created from what the birds knew over 50 years ago. In 2006, we had over 200 known nesting pairs of peregrine falcons, and the population continues to appear to increase in some states. The majority of the nesting sites are buildings (46%), followed by cliffs (28%), smokestacks (16%) and bridges (10%).
Colonnade female on eggs
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In 2006, the field team was surprised to discover birds incubating eggs almost 3 weeks earlier than the pair had done in previous years. This year is proving to be the same, with some sites even 7-10 days earlier with egg laying than they were in 2006. However, other sites appear to be on their own time-table and are on course for laying eggs as they had for the previous 8-10 years. It is a great example of humans realizing they are NOT in control and the birds are going to do what they need to do, when they chose to do it…for a Type A personality (i.e. Control Freak!!) like myself, this can be a difficult thing to let go of and to allow the birds to have the control. I will admit, I am accepting this fact much better this year than I may have last year. |
Generally 3-4 reddish/brown mottled eggs are found in the majority of the nests in our state. Occasionally we find a nest with 5 eggs but it is rare for all five to hatch and fledge, although it does occur in some sites in other states. Generally speaking, incubation will range from 33-35 days, and begin with either the last or the next to last egg that was laid. In high latitudes and cold climates, incubation may begin after first or second egg, depending on conditions, with staggered hatching. |
Close-up of an egg
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Wells Fargo female guards her nest
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So far, the field team has observed eggs and incubating behavior occurring at the following territories-the Mayo Clinic in Rochester, Queen’s Bluff near Winona, the Bremer Tower in St. Paul, the Colonnade building in Golden Valley, the Cedar Riverside Plaza and Lock and Dam #1 in Minneapolis, the St. Cloud prison in St. Cloud, and the Sartell Paper mill in Sartell. Sites such as City Hall and City Center in Minneapolis, and the Wells Fargo building in Bloomington are not far behind. Basically, we should know the success of the sites by the last week in April or first week in May. Make sure to check back with us to see how the sites are doing. If all goes well, we should be banding the young peregrines around Memorial Day. |
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