Egg-laying is just around the corner for our peregrine falcons! The earliest layers – Great Spirit Bluff is usually among them – tend to begin in late March, although egg-laying can continue into late May at some of our nests. After the first couple of years and absent mate changeover, falcons tend to lay their first egg on or around the same date every year, although eggs usually come a little later in cold, dry years.
When should we look for eggs at Great Spirit Bluff? It depends on who ends up nesting with Newman! He has courted at least four females this year: 53/M KJ, a 2016 hatch from the Racine County Courthouse in Racine, WI; an unbanded female that we believe was Nova; Amhran 92/X, a 2018 hatch from Skidmore Bluff in Hagar, WI; and Nina M/04, a 2019 hatch from the University of Wisconsin in Milwaukee.
Long-time watchers will remember Michelle, who nested at Great Spirit Bluff from 2011 through 2019. She tended to begin laying eggs between March 27 and April 2. Nova, the third female at Great Spirit Bluff, laid her first egg on March 26 of 2020. If Nova stays, we might expect her first egg on or a little before March 26 – like bald eagles, falcons often move a little earlier after their first year or two of laying eggs. But we’re seeing a lot more of Nina M/04 right now, so we really don’t know what to expect. Most of the falcons we watch begin laying eggs in the first two weeks of April.
What’s Going on At Great Spirit Bluff?
Like bald eagles, peregrine falcons were long considered to be monogamous. It’s more or less true if your idea of monogamy includes deadly mate competitions, winner take all! As we’ve seen before, Newman is more than happy to welcome and court female falcons this time of the year, established mate or no. Bob believed that peregrine falcons were bonded first to place and secondly to mates – which is exactly what we’re seeing at Great Spirit Bluff.
Did one of the falcons that Newman is courting kill Nova? Not necessarily. Falcon fights aren’t always to the death: one female can chase another off. That female might come back later to try to reclaim her nest, might try to take another nest, or might skip breeding entirely that year.
Why are so many female falcons showing up at the bluff this year? Males come back from migration earlier than females. They set up territories and attract returning females with fancy flying, vocalizations, and food gifts. Without a mate, Newman is courting every female that wanders by his territory: and we are at peak return time for female falcons! Most breeding females will be on their territories by mid-March, so it won’t be long until this season’s The Bird Bachelor concludes.
This isn’t the first time that Nina has visited Great Spirit Bluff. She stopped by and said ‘Hello’ to Newman while he was incubating on April 13 last year. At the time, she was a one-year-old falcon. He looked at her, but didn’t really interact. It seems like she remembered their encounter!
Peregrine falcons will take new mates, but polygyny is fairly rare. They do not appear to engage in extra-pair copulations, aka promiscuous mating in monogamous species or, as some of you call it, cheating.
The Peregrine Falcon is the fastest animal in the world, diving or stooping at speeds that can reach over 200 miles per hour. Almost everything about it is built for speed, from the baffles in its nose to the jagged edges of its slim, stiff feathers and long, pointed wings.
A Peregrine Falcon catches other birds in flight by diving on them from above. As she begins her stoop, she rolls, cups her wings around her body, and tucks in her feet. This change in shape streamlines her profile, yielding an aerodynamic raindrop that can cut through the air at high speeds.
March 22, 2020: Diving Peregrine Falcon. Photo used with permission of Karen Carroll at http://www.birdsofprey.net
As she plummets, her nictitating membrane protects her eyes from dust and debris in the air and a secretory gland helps keep her corneas from drying up. A special cone or baffle in her nose regulates the amount of air entering her nasal cavity, allowing her to breathe and protecting her from damage. A curved flight path keeps her prey in view and allows her to respond to last-minute escape attempts without losing lift. Before she strikes her prey, she’ll experience G-Forces estimated at between 25-27 Gs.
The peregrine meets her prey feet-first. She slows first, unfurling her wings and tail, and dropping her feet. After striking and stunning or killing it outright, she’ll loop around in mid-air to retrieve it and take it to a safe place for plucking and eating.
Falcon Belinda at Xcel Energy’s Allen S. King plant takes aim at a reporter
Lifestyles of the Fast and Furious
Falcons are roughly crow-sized. Females are about a third larger than males, although they both have blu’ish to slate grey backs, barred or streaked white to rusty underparts, and a dark hood. Adults have black beaks and yellow feet, although their babies may initially have bluish feet. This is natural and not a cause for alarm.
Both males and females are highly territorial. We believe that they are fairly solitary birds even off their nesting grounds, although groups of young peregrines have been reported on oil platforms and ships in the Gulf of Mexico. I would love to see more studies on their ‘wandering years’ and wintering grounds. We know very little about their behavior off-territory.
Traditionally, Peregrine falcons nest on cliffs, laying their eggs directly on a scrape they created in a gravel or sandy substrate. In the Midwest, Peregrine falcons generally:
- Lay eggs in late March or early April
- Hatch in late April to early May, or 33 days after the first egg is laid.
- Begin flying in mid-June or later, or about 40 days after hatch.
Peregrines are excellent, attentive parents. The babies cannot thermoregulate (control their temperature) until they are about 10 days old, so Mom spends a great deal of time huddling over them while Dad feeds everyone. As the babies age, both parents spend time hunting. The eyrie is small and the babies, which have among the fastest growth rates in the animal kingdom, are large and hungry. They eat, sleep, poop, and go from white fuzzballs to sleek brown juveniles in 38-40 days.
Once they begin flying, young peregrines spend a lot of learning how to fly and hunt: something that looks a lot like play to most human observers. Their parents will continue to provide some food for their newly fledged young who are not yet self-sufficient. Come fall, the adults may or may not migrate, but their children will disperse between mid-July and early September. Once they are gone, they are gone. If they do come back to the nest, their parents will defend it from them.
What to expect when falcons are expecting
You can watch for peregrine falcon courtship at any of our nests, although Great Spirit Bluff is my favorite! Watch for fancy flying (the male or tiercel falcon flies acrobatically, sometimes wiggling his tail as he goes), bowing, scraping, and incredible fly-in copulations. Males will gift females with food, and both sexes will work on a scrape, digging into the gravel with their breasts and pushing with their legs to create a depression into which the female will lay her eggs. Falcons do not create tree nests, although they have been documented laying eggs in unused Bald Eagle nests.
Female falcons will begin laying three to four reddish speckled eggs sometime in late March or early April. Peregrine falcons do not begin full incubation until after egg number three is laid, so it is normal for them to spend time – even quite a bit of time, depending on how warm it is – away from eggs number one and two. Eggs should begin hatching roughly 33 days after the third egg is laid.
During incubation, falcons experience hormonal changes that help keep them incubating. They may appear sleepy or lethargic as they pick at gravel and sit on their eggs. Females do most of the incubation, although their mates will spell them briefly during the day. Smaller males sometimes have a harder time covering all of the eggs, depending how many are laid. We can also expect to see egg rolling and some shimmying. This is not a particularly active time for the falcons: Bob used to refer to incubation as the ‘egg doldrums’.