See all the video and photo highlights using the interactive timeline. The timeline also includes events from last year.
See the Timeline.
This is one of several osprey nests in the county. In the spring of 2003, this osprey pair began nesting on a light pole at the Boulder County Fairgrounds and returned each year. In 2009, wildlife biologists moved the nest to its current location just east of the Cattail pond for the birds' safety. The pair shifted to the new location with ease.
Our biologists believe that the local surge in nests may be offspring returning to their previous habitat area.
Migration
Osprey migrate far to the south every year to Central or South America. The male, female, and offspring all go their separate ways. The male and female migrate and winter separately but return to the same nesting site each year. Offspring usually remain at their wintering grounds for their entire first year before beginning a migration and nesting pattern. There are no markings to indicate which osprey is male and which is female, but the females are generally larger than the males. They show up around the first of April and complete mating and egg-laying within the first two weeks after both have arrived. They leave between September and October, after the chicks have fledged.
Other birds utilize the platform whether the osprey are present or not. Last year magpies and blackbirds were on the platform or camera when the osprey were on the nest. Smaller birds can nest in the nest material and are usually ignored by the osprey. This year we have had a Great Blue Heron perching frequently on the platform with no apparent disruption to the osprey.
Diet
The osprey is the only local raptor that almost exclusively hunts fish. On rare occasions, they will eat squirrel or muskrat. Osprey will sometimes scout for fish from its nest. Once a fish is spotted, the osprey will drop down in the water fully submerged. Their dense and oily feathers allow them to come back out of the water and fly away. They are successful just over half the time on that first dive. Some of the public places you can see them fishing are: both Fairgrounds lakes, Twin Peaks golf course, Lagerman Reservoir, and Pella Crossing.
The Nest
The nest is mainly used for the osprey's offspring. The nests have to be wide enough to support up to six full-sized birds. Osprey nests weight an average of 400 pounds and are amended yearly. No one knows why they collect all the different things that they do for their nest (including trash), other than to make the lining soft and to keep eggs from falling into voids in the stick nest. Osprey chicks only have a 50% chance of surviving their first year.
Learn More
Learn more about osprey at the Cornell Lab of Ornithology.