Carol O'Meara - Colorado State University Extension

Carol O’Meara – Colorado State University Extension

BOULDER COUNTY – As feathered friends take up song and begin the year, indulge me while I talk about a non-gardening topic. High above the Boulder County Fairgrounds drama has unfolded, capturing the attention – and imagination – of fans.

The resident ospreys returned for the summer and they opened the season like avian Kardashians, with strange females, a two-timing male, bad boy attacks, and the struggles of a female to keep her man. Via the live feed from the Osprey Cam, fans tune in from across the globe to watch the pair and offer thoughts (and sometimes judgements) on the nesting and mating habits of the pair.

Ospreys are large, fish hunting raptors that nest near large bodies of water and build huge, stick based nests. They occur on every continent except for Antarctica. Boulder County Parks and Open Space Wildlife Biologist Michelle Durant said that, within five miles of the Fairgrounds, there are approximately six pairs of nesting ospreys and they believe a total of 10 nesting pairs are in the county.

[pullquote] LIVE OSPREY CAM
Keep an eye on the Osprey
pair via the Boulder County
Osprey Cam:
bouldercounty.org/os/
openspace/pages/
ospreycamera.aspx
[/pullquote]

“Occasionally an unknown, new, or extraneous pair attempts to nest near a current pair, but they’re not always successful. The resident nesting pair often spend time fending off these intruders, which can take away from time they spend caring for their own eggs or young, ” Durant said.

Migratory, our ospreys return to the area in March. Mated pairs return to the same nest yearly, which brings us to the current drama being seen on our Real Ospreys of Boulder County video feed when an unknown female arrived at the nest March 9. Shortly after, the resident male arrived and, since the resident female wasn’t around, the two did things that raised eyebrows.

“Ospreys are monogamous, but they’re bonded to the nest more than to a mate. If there’s no other female around, the male will mate with whoever is here,” says Jasmine Finks, volunteer co-moderator of the Osprey Cam with Steph Powers. Such caddish behavior is accepted in ospreys. The interloper strutted about the nest, protecting it as if it were hers. A second, then a third unknown female visited; an unknown male made a brief attack run. Clearly this nest – festooned with plastic flotsam the male finds irresistible – is prime real estate.

But then the Resident Female arrived on March 25 and addressed the shenanigans. “She’s usually fashionably late compared to other area ospreys. Perhaps she migrates farther,” said Finks. Feathers were ruffled, then flew in a brief scuffle, and the usurping female fled (https://youtu.be/CsLgw0hyfkg).

Now the male pays loving attention to his one and only: he nurtures her, and she him, gently bumping together as they repair the nest or bringing each other fish. Powers speculates that this is one reason our ospreys are popular worldwide – it’s unusual for them to care for each other. But he knows she can look out for herself, as evidenced by his calmly sitting while she’s pursued by an enraged Red Wing Blackbird chasing her around. It’s just another day at the nest.

Keep an eye on the pair via the Osprey Cam bouldercounty.org/os/openspace/pages/ospreycamera.aspx or head out early in the morning to watch them at Isaak Walton pond in Longmont, a favorite fishing hole for the male. “He’s a great fisherman,” said Powers, “he can dive and come up with two fish. One in each talon.”

Eggs are expected in about two weeks and the pair typically lays four. Osprey can delay the incubation of eggs until all four are laid simply by not sitting on them. Tragedy struck last year when three of the four perished in hours after hatch; we’re hoping all are healthy this year. The number of young produced annually by each nest varies year-to-year, but typically one to three young fledge by late summer.

By Carol O’Meara, Colorado State University Extension
Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail comeara@bouldercounty.org or visit ext.colostate.edu/boulder.