Tag Archives: Unusual

Bald Eagles: A Fission-Fusion Species?

March 5, 2020: We saw our first large multi-age group of eagles today! They follow the melt north, gorging on gizzard shad and other fish they find in the ice.

While some websites state that Harris Hawks are the only raptors that hunt communally, social hunting – sometimes in mated pairs, and sometimes including unpaired birds, depending on the species – has also been documented in Bald Eagles, Golden Eagles, Striated Caracaras, Red-tailed Hawks, Ferruginous Hawks, Red-shouldered Hawks, Peregrine Falcons, Lanner Falcons, Aplomado Falcons, Philippine Eagles, and Verreaux’s Eagles. Some of these species are loners, but others – including bald eagles – appear to be a fission-fusion species: i.e., they

DH2 and the Red-Winged Blackbird

DH2 and the red-winged blackbird

We think we saw DH2 soaring over the hatchery on Saturday, July 22nd, although the eaglet was missing its red-winged blackbird escort, so we can’t be entirely certain. Male red-winged blackbirds are very territorial and we often see them harass eagles, including Mom, Dad, DM2, HD, and HM and many of the 40 eaglets produced on the hatchery territory. But this year’s level of attention has been unique! We don’t think this video shows interspecific allopreening, which has only been

Bald Eagle D36 has died

June 30, 2020: D36 and the eagle team

We are beyond sorry to announce that bald eagle D36 has died. Bald eagles die and this isn’t the first time we’ve had to announce it. But this feels especially tragic. For almost the first time since we started tracking eaglets from Decorah back in 2011, we won’t be following one. We started tracking them to answer one of the most common questions that followers asked: ‘Where do the Decorah Eagles go?’. They taught us a whole lot about their

Will HM’s eggs hatch?

March 14, 2023: HM shortly before leaving the nest.

On Tuesday March 14th, two brush pile burns were conducted south of the Decorah Eagles nest near the hatchery. During the early morning, the wind was blowing to the south, which carried smoke away from the nest. But at about 10:00 AM, the wind switched direction and began carrying smoke north toward the nest. Wind speed also increased from about 2.2 to about 9.2 miles per hour, which blew even more smoke and some light ash as the day progressed.

Nest-guarding and intraspecific intrusions

March 16, 2023: Mr. North and his last evening of incubation.

The Decorah North Eagles have been dealing with a lot of intraspecific intrusions this year. Intrusions happen when members of other species encroach on or enter a nest in search of food, nesting materials, or a nest: think squirrels, mice, raccoons, chickadees, woodpeckers, red-tailed hawks, house sparrows, and other animals we’ve seen in and around our nests. Intraspecific intrusions happen when other eagles intrude on daily nest activities in search of food, new mates, or breeding territories. They can lead

What’s Going on at the North Nest?

February 24, 2023: DNF and Mr. North back on the North nest.

North nest watchers know that 2023 is off to a very unusual start. DNF has laid her first egg on February 16th for two years in a row and her average first lay date, excluding her first year, is February 17. We were surprised when she didn’t lay her first egg until February 20th, especially after her extended stay in the nest on the night of February 14. Male and female eagles both incubate eggs, but female eagles almost always

February 7, 2023: What happened to HD’s foot?

February 7, 2023: HD's foot.

What happened to HD’s foot? On February 3, several sharp-eyed volunteers and fans noticed that one of his toes appeared to be injured. We talked with Dr. Laura Johnson and Master Bander Dave Kester about the injury. What’s going on? It isn’t easy to diagnose a condition based on photos, but Laura told us that it looks like an injury (possibly a constriction or bite) caused a loss of blood supply to HD’s toe and nailbed. We first noticed the

Nest N3 destroyed in the strong storms that rolled across NE Iowa on Saturday night

July 28, 2022: The view from the trail behind Walmart. N3 is gone. Many of the dead trees (and some of the live ones) either fell or took damage from the wind and other trees.

Nest N3 – the nest that Mom and DM2 built behind the Walmart in the fall of 2020 – was destroyed when the nest tree fell in the strong storms that rolled across NE Iowa on Saturday night. Based on the debris line and flattened, muddy grass along the upper Iowa behind Walmart, the river was at one point roughly four feet over its current flow level. The discharge in cubic feet per second more than tripled overnight following 4+

June 14, 2022: Fall at Great Spirit Bluff

June 14, 2022: Falcon falls from Great Spirit Bluff

The falcons at Great Spirit Bluff have jumped out of the box. We originally thought that we were seeing some exploratory behavior, but it looks like the blackflies drove the youngest falcon out before the older two. We’ve been asked if we plan to go down and rescue them. For now, we’re leaving them alone. It is our experience that falcon parents will take care of their young by flying into the understory to find, feed, and defend them. We

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