In two previous posts I’ve written about the methods that young captive-bred, costume-reared whooping cranes are released into the wild. The best known, the Ultralight Method by which young whoopers are taught a migration route by following ultralight aircraft has been used to build the Eastern Migratory Population (the EMP) of whooping cranes in Wisconsin, since 2000. There are 6 ultralight-trained whoopers this year that have already begun – their schedule dictated by the winds and weather – to follow the ultralights south.
Not so well-known, but very well-tested, the Direct Autumn Release method has been used since 2005, and has also added a significant number of cranes into the EMP. With this method young whoopers, after costume-rearing as tiny chicks at the International Crane Foundation, are released into the wild as young colts near adult cranes; it is hoped they will follow the adults on migration. There are eight DAR birds this year, currently being monitored at Horicon National Wildlife Refuge.
For the past three years a completely new experiment, known as the Parent-Reared Method for releasing chicks from the captive populations into Wisconsin, has been tried.
This Parent-Reared program originates from Patuxent Wildlife Research Center, which is home to the original captive flock of whooping cranes. (Patuxent, in Maryland, is also where the ultralight chicks are hatched each year, and receive intensive training from the costume-rearing staff until they are old enough for their flight training with the ultralights in Wisconsin).
The Parent-Reared program was authorized for only three years, and involves only a handful of birds. Yet, in the future, according to Anne Lacey at the International Crane Foundation, it just might help the EMP reach the elusive goal of reproductive success.
But that’s getting ahead of the story for now. Here’s how the Parent-Reared release program was set up, and how it is working. In marked departure from both the Ultralight and the DAR programs, there are no costumed humans nurturing these young cranes. They did not hatch from eggs in man-made incubators, but instead from an egg that was incubated by their actual whooping crane parents.
After hatching, these chicks are reared by their whooper parents until they can fly. Once the chicks have fledged, the adult whooping cranes’ jobs are done, and the chicks are separated from them in preparation for their transfer to Wisconsin. Before the actual move, however, the 3 or 4 chicks – or colts (they are nearly adult-size now) – raised for this program are kept together at Patuxent, and given a bit of time to bond with each other.
They are then crated and flown here (to Wisconsin), Once here, and uncrated, they are kept together overnight at the International Crane Foundation. Meanwhile at Necedah NWR, a temporary pen has been set up for each crane near territory that is inhabited by an established pair of adult whoopers, in hopes that the adults will adopt the youngster and take it with them on migration.
Ann Lacey told me that sometimes this works like a charm. The adult pair take note right away that there is a new young colt on their territory, and seem to take a keen interest in it. When that happens they do quickly adopt it once it has been released from the pen (after just a few days). Other times the adult pair may simply tolerate the young bird, and not show a lot of interest, but will still allow it to hang around them.
Three new parent-reared birds have been released at Necedah this year. There were a total of just eight birds released through the parent-reared method in 2013 and 2014. Three of them died within a month of being released at Necedah, and five have survived to migrate and return to Wisconsin (and that’s twice, for the two surviving parent-reared birds from 2013).
A clear majority of these parent-reared birds are surviving, so there’s an affirmative answer to the question in the headline of this post “Can captive parent birds raise a bird for the wild?” It’s apparent they can. But here’s another question: how can these birds be the solution to the Wisconsin cranes’ reproductive success? Is the thought that they would be better parents?
And that brings up a number of other questions, including some about the Wisconsin cranes’ most recent breeding season. Sounds like questions for another post; I’ll just leave it there for now.