Last year when we released the parent reared birds, we did it where the adults were foraging during the day. In fact, we even put a few of them in temporary pens in hopes that the adults would be attracted to them long enough to form a bond.
Sometimes it worked. Jo-Anne and Heather monitored number 38-16 for three days in Marquette County last year while the adults spent most of their day around its pen. That connection continued when the chick was released but it, and another (31-16) released there failed to follow them to their roost site a few miles away. They would circle overhead and call to them but the chicks could only make short flights around the field.
On the other hand, number 30-16 spent time in a pen near White River Marsh where two pairs of adults completely ignored him for three days. Once he was released, he became the only 2016 Parent-Reared crane to be properly adopted.
Cranes raised in captivity don’t get to fly like wild birds. Once they are released, their poor flying ability could be under-developed muscles, a lack of experience, or a combination of both. Either way, it’s dangerous for cranes to roost on dry land.
So this year we are attempting to release the Parent-Reared chicks where the adults roost. That way, even if it takes them a few days to practice flying, they still have a safe place to spend the dangerous nights. Hopefully, after a few days they will follow the adults to their foraging grounds and that bond will have a chance to form.
One minor advantage of releasing them where the adults forage is that they can generally be monitored more easily. Open fields allow us to record the amount of time they spend together and their behavior. Now that most of them are in isolated wetlands, there isn’t much we can do except check on their location a few times a day. Remote tracking gives us a picture of their movements and habitat use but not how they are interacting with adult cranes.
Each released crane has a VHF transmitter on one leg, which emits a signal. The following clip show the receiver and antenna and the audible beep we hear when trying to determine the location of a bird we cannot see.