When people see the large nest inside the Dickinson County Nature Center and the big raptors on the outdoor nest during the summer, they often think they are bald eagles.
Many people don't realize that after being extirpated in Iowa, osprey populations have started to make a comeback in the 2000s. Each summer, osprey come to Kenue Park to nest and raise their chicks before heading south for the winter.
Even after learning about osprey, people have trouble telling the difference between them and bald eagles. Other than their coloring being different, there are seven other key differences between osprey (Pandion haliaetus) and bald eagles (Haliaeetus leucocephalus).
1. Size: Osprey have an average 59- to 70-inch wingspan and weigh 3-4 pounds. They have long, narrow wings with a marked kink that makes them look like an M-shape from below.
The bald eagle is one of the largest birds in North America, with an average 80-inch wingspan and weighing 6.5 to almost 14 pounds.
2. Diet: Osprey eat a diet of about 99 percent fish, usually 4-12 inches long. The type of fish varies depending on where in the world the osprey lives, but the osprey in Okoboji seem to enjoy panfish and the occasional koi from a local water feature.
Bald eagles love fish as well, and sometimes rather than doing their own hunting they will harass osprey, making them drop their fish or even steal their fish right out of their talons.
Bald eagles also eat birds, reptiles, amphibians, rabbits and muskrat, both live or as carrion. They sometimes gorge on food and digest it over several days, and they can also survive fasting for many days or even weeks.
Beak: An osprey's beak is black, short and has a sharp hook that helps it tear into fish to eat.
Bald eagles have a yellow beak which is also hooked for tearing into flesh.
Talons: Osprey have extremely long, curved and sharp talons that help them grip the fish they catch. Their white feet have spiny scales, and they also have four equal toes. The outer toe is reversible, allowing the osprey to hold its fish aerodynamically when it flies.
Eagles have giant talons on their first and second toes that give them a secure grip on struggling game. They also have yellow feet.
Special abilities: Osprey can dive about three feet into the water to catch fish, and they can dive both head and feet first. They also have the ability to take off straight from the water instead of having to swim to shore.
Sometimes bald eagles hunt cooperatively, with one individual flushing prey toward another.
Nest: Osprey nests are built of sticks and lined with bark, sod, grasses, corn stalks and other softer materials. Most nesting platforms are about 5 feet wide and a foot deep. However, it has been seen that osprey who nest in the same place year after year have ended up with nests 10-13 feet deep and 3-6 feet in diameter.
Osprey also like to nest in open areas, usually built on snags, treetops, cliffs or human-built platforms, cell phone towers or light towers.
Bald eagles nest in trees, usually conifers, and create huge nests --- 5-6 feet wide and 2-4 feet deep --- out of sticks lined with grass, moss or corn stalks. Nests can take up to three months to build. Bald eagles typically build near the trunk of a tree, high but not at the crown like osprey. Some eagles also nest on the ground when necessary, using kelp or driftwood for construction near coastal shorelines.
Chicks: Osprey typically lay 1-4 eggs once per season. Eggs are cream-colored and spotted with reddish brown dots. The incubation period is 36-42 days, and the chicks usually fledge within 55 days.
Bald eagles lay 1-3 eggs once per season. Eggs are dull white, usually without markings. The incubation period is 34-36 days, and chicks stay in the nest 56-98 days.
Spring is coming, and that means that we starting looking for the Okoboji osprey to return to the nest in Kenue Park. They are amazing creatures that follow a strict schedule, and you can almost set your watch by them. Here is a quick timeline of the typical osprey year: April 2: After overwintering in…Read More
In the movies, you have probably seen a bald eagle flying and heard a screech-sound effect. However, that’s actually not a bald eagle’s call (hear that here). You may have also seen an osprey flying overhead in the movies and heard the same call, or a golden eagle and heard the same call. Film production…Read More
1. Bald eagles don’t sound as tough as they look. If you hear a bald eagle in a movie, it is usually dubbed over with a red-tailed hawk call. Producers think bald eagles sound too wimpy. Above is the bald eagle, below is the red-tailed hawk. 2. Bald eagles have huge nests. Bald eagle nests…Read More
The bald eagle is the national symbol, so Independence Day week is the perfect time for a bald eagle craft. Plus, why not reuse some materials while you’re doing it? For this toilet paper tube bald eagle, you’ll need just a few supplies: Empty toilet paper tube Black, white, yellow/orange cardstock Googly eyes (optional, or…Read More
Osprey are unique raptors that are built to eat fish, in fact, it’s 99 percent of their diet. Click on the image below for a free printable osprey maze activity that you can challenge yourself with at home. Read more about osprey at these links: WATCH: Osprey lifespan Seven differences between osprey and bald eagles…Read More
From migrating north to reproduction and caring for chicks to migration south, the osprey lifespan is fascinating! Don’t forget to download the Okoboji Osprey Activity Book complete with word search, dot-to-dot and Migration Mad Libs. Click here to access the free activity book.Read More