False eyes

7-27-16 Aldo at Lakewoods.jpg

Sometimes even a kestrel needs time to relax after a busy day of work. Aldo had the opportunity to enjoy the view of Lake Namakagon after an outreach program at Lakewoods Resort this week.  As he watched boaters coming and going on the lake, I had a great view of the back of his head. In this photo, you can see the black spots on his nape. These “ocelli” are thought to act as false eyes. They might protect the kestrel from a predator like a Cooper’s or Red-tailed Hawk. The spots might also prevent angry songbirds from getting too close when trying to chase off a kestrel. In either case, they will wait to attack until they have the element of surprise. If the kestrel’s trick works, the attacker will choose to back down rather than risk getting tangled in the talons of the seemingly vigilant kestrel. The false eyes are a simple illusion that helps wild American Kestrels enjoy a nice view without worrying too much about predators.

Staying cool

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Aldo cools off after being misted with water.

If we’re baking in the heat wave this week, the birds are feeling it, too. Feathers, so important for flight, act like a down jacket (literally!) even during the summer months.  Luckily the Museum’s raptor species are all native to Wisconsin and are built to manage the temperature extremes we see throughout the year.  In the heat, they can increase their breathing rate or take a bath to cool off.  They have bare skin exposed on their legs and feet, and can raise their feathers to allow air movement close to the skin.   While they can’t sweat like we do, they use evaporative cooling more like dogs by panting (“gular fluttering” is the bird-specific term).  We will also help our birds stay cool by installing fans outside the mew for air circulation or misting them with water.  It’s not uncommon for the handler to get misted, too, and on a day like today it’s probably on purpose!

Eye color

7-15-16 Carson.jpg

When I first met Carson, our resident red-tailed hawk, I was fascinated by her eyes.  The light grey iris was striking compared to the dark eyes of other hawks I have known.  This isn’t just a difference between individuals; eye color hints at the bird’s age.   Red-tailed hawks hatch with light-colored eyes that darken over time.  Carson is just three years old now, so we expect her eyes to turn a dark mahogany over the next few years.  Some other raptors change eye color, as well.  Eagle eyes change from brown to yellow, while sharp-shinned hawks start bright yellow and transition to a blood red.  We can’t know for sure why this happens, but it may be an important cue for birds looking for a mature mate.