GSB Peregrine Falcons

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La Crosse
70°
moderate rain
humidity: 83%
wind: 16mph S
H 80 • L 78
About the GSB Peregrine Falcons
General Information

The Great Spirit Bluff peregrine falcons are nesting on a bluff located near La Crescent, MN, overlooking Lock and Dam #7 on the Mississippi River. The peregrines are not present year-round. In general, they return in late February to early March, begin courtship between early and Mid-March, and lay eggs between late March and mid-April. Hatch should begin in early to mid-May, fledge generally occurs 38-40 days after that, and young disperse in late August or mid-September. The adults stay on territory until late fall. While the male and female leave at roughly the same time, they are not believed to migrate together.

Peregrine falcons do not build nests out of sticks. They make scrape nests on ledges, potholes, and crevices on cliffs and buildings. This nest box is filled with pea gravel to provide a substrate that cushions and drains the eggs. We installed it in 2003 at the request of Tom Howe. It became active in 2005 and has been productive ever since.

Peregrine falcons feed primarily on birds that they catch in the air. To learn more about peregrine falcons in general, please follow this link to the Cornell Lab of Ornithology website: http://www.allaboutbirds.org/guide/Peregrine_Falcon/id. To catch up on videos of Great Spirit Bluff, please visit our YouTube channel or scroll farther down this page.

Quick facts
Seen/Heard at
Great Spirit Bluff, Decorah North

Diet
Peregrine Falcons feed primarily on other birds they catch in the air. We’ve found the remains of Pie-billed Grebes, Pigeons, American Robins, Blue Jays, Grackles, Cedar Waxwings, Gulls, Yellow-shafted Flickers, Bluejays, Wilson’s Snipe, Mallards, Gulls, Killdeer, Downy Woodpeckers, Hairy Woodpeckers, Terns, Soras, Rails, and Baltimore Orioles. In general, the prey remains we find reflect local birds, although peregrines seem to have a preference for large birds, most likely because they provide a larger meal for the amount of effort expended.

Peregrine Falcons have also been documented eating small mammals and carrion. Scavenging is more common in younger birds than older birds, and may be more common in some biomes than others. Kleptoparasitism may also be more common than we know. It has been documented in Spain (Carrion Crows), Russia (Imperial Eagles, Osprey), and the United States (Osprey, unknown bird of prey). In most cases, a Peregrine Falcon attacked another bird that was carrying prey. When the attacked bird dropped it, the Peregrine Falcon recovered it from the air and flew away to eat it elsewhere or bring the stolen prey back to the nest for young. Bob found a fish in a peregrine nest in Minneapolis and we witnessed a female falcon at Great River Energy bring in a 13-lined ground squirrel in 2008. Falcon Michelle brought in little brown bats at Great Spirit Bluff in 2016 and 2017, although they aren’t a common prey item. This video shows her eating a bat before civil sunrise, which indicates she was out hunting before daybreak: https://youtu.be/hblwIr0nuAY.

Nesting
Peregrine Falcons breed from mid-March through early June (although reproductive activities may start in early February). They usually nest on ledges and in potholes, crevices, and nest boxes, although they sometimes choose open gravel-topped roofs and gutters. Males establish territories and court females with display flights and gifts of food. Peregrine nests are often started by males, who use their feet and bodies to scrape shallow depressions in whatever substrate is available, including dirt, sand, pebbles, sawdust, nesting debris, gutter run-off, and gravel. Females assist in later stages of construction by tailoring the scrape to their liking. Peregrine falcons lay two to four eggs per clutch and produce one brood per year. Both parents incubate eggs for 32-36 days and young stay in the nest for 38-41 days. To learn more, visit Cornell’s website.

Although it isn’t common, tree nesting has been documented in peregrine falcons in the United States as recently as 2013. The authors of the short communication Tree-Nesting by Peregrine Falcons in North America: Historical and Additional Records reviewed literature and found 33 North American records of peregrine falcons nesting in trees or snags in Alaska, Kansas, Illinois, Tennessee, Louisiana, Virginia, and British Columbia. You can read more about that here: https://raptorresource.blogspot.com/2017/05/a-peregrine-falcon-at-decorah-north-nest.html.

Citations
Bird Range Maps of North America
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003.
Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA. Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy – Migratory Bird Program, Conservation International – CABS, World Wildlife Fund – US, and Environment Canada – WILDSPACE.
Web Link: http://bit.ly/2ynPQ5I
The Cornell Lab of Ornithology Birds of North America: https://birdsna.org/Species-Account/bna/species/perfal/introduction.
Kleptoparasitism – one of hunting technique of the Peregrine Falcon that became common under condition of the increase in its number in the Southern Ural Mountains, Russia: http://rrrcn.ru/en/archives/19448.
A Peregrine falcon at the Decorah North Nest! https://raptorresource.blogspot.com/2017/05/a-peregrine-falcon-at-decorah-north-nest.html.


General Description
Adult Peregrine Falcons have slate blue upper parts with white barred underparts. They have dark heads, pale cheeks, and a mallar stripe (or mustache) that extends downwards from their eye. Their breasts may be all-white or contain a buff, salmon, or peach color. Juveniles are brown and heavily marked, with vertical streaks instead of horizontal bars on the breast.

Migration
Migratory sighting in Decorah, resident and migratory sightings at Great Spirit Bluff. Peregrine Falcons are partial migrators: some migrate and some do not. Our birds have been reported on oil rigs in the Gulf of Mexico, on beaches in Cancun, and in the forests of Costa Rica. They do not live in the Decorah area as far as we know.

Measurements
Length: 14.2-19.3 in/36-49 cm
Wingspan: 39.4-43.3 in/100-110 cm
Weight: 18.7-56.4 oz/530-1600 g

Wing Design
High Speed Wings. Peregrine falcons are the world’s fastest flyers, and their long, pointed wings reflect their high-speed flight.

News
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Nest Records

Egg #1: April 2, 2019 @ 8:29 AM CDT
Egg #2: April 4, 2019 @ 9:40 PM CDT
Egg #3: April 7, 2019 @ 1:00 PM CDT
Egg #4: April 10, 2019. First seen at 5:30 AM CDT

Hatch #1: May 12 @ 4:53 PM CDT
Hatch #2: May 14 @ 6:52 PM CDT

Eyasses and Outcomes    >>

 YearMom Dad# of young produced
2018Michelle P/87Newman (unbanded)2
2017Michelle P/87Newman (unbanded)2
2016Michelle P/87Newman (unbanded)4
2015Michelle P/87Travis 06/N4
2014Michelle P/87Travis 06/N1
2013Michelle P/87Travis 06/N3
2012Michelle P/87Travis 06/N2
2011Michelle P/87Travis 06/N4
2010UnknownUnknown4
2009UnknownUnknown4
2008Unknown (b/r)Unknown1
2007UnknownUnknown3
2006Katrinka 59/EUnknown3
2005Katrinka 59/EUnknown (b/g)4

To date, 41 young have been produced here since the site became active in 2005.

  • In 2018, two of four eggs hatched. We did not have blackfly problems this year and both falcons survived to fledge at around 40 days of age.
  • In 2017, all four eggs hatched. Two young falcons were killed by black flies on 5/22/17. Survivors Hamilton and Burr-D jumped from the nest on 6/03/17 following a black fly swarm, but survived to fledge.
  • In 2014, just one egg hatched. Male Mac was driven from the nest by blackflies when he was 32 days old. He fledged from the ground after his parents found and cared for him.
  • In 2013, all four young falcons were driven from the nestbox by blackflies when they were around 30 days of age. One was found and fostered to another nest box, two fledged successfully from the ground after their parents found and cared for them, and one disappeared.
  • In 2012, young falcon 87/W (Cassie) disappeared from the nestbox. 86/W (Christine) was found dead at the LaCrosse airport.
  • Falcon Laura, a 2009 hatch, is currently nesting at Red Wing Grain in Red Wing, MN.

Adults

Female Michelle P/87 and male Newman (unbanded falcon named by the Howe family) are currently nesting here. As far as we know, former resident male Travis 06/N did not return this year.

Videos

GSB Video Playlist

Click the icon on the top left of the stream to view a full list of videos from our 2019 playlist, or visit our our YouTube channel.