Eastern Flock "Family Tree"
Crane Siblings Get Together as Mates?
Stehn, Whooping Crane Recovery Team
the eggs for the new Eastern flock have come from Whooping Cranes in
you know that the Eastern flock cranes include many siblings? Cranes
that are produced by the same Sire and Dam (parents) for each project
year are siblings. You can check out their "Family
might wonder: Will any of the siblings (chicks who come
parents) get together as mates? What are the genetic risks, if any?
We asked this question of Tom
Stehn, Whooping Crane Coordinator for
the USFWS. Here's
know if Whooping Crane siblings would have any mechanism to avoid
with each other. Certainly siblings produced in the same year from
the same nest (Whooping Cranes occasionally are able to have both
chicks they hatch every year survive), those siblings probably would
never attempt to breed with each other. In captivity, Whooping Crane
juveniles raised together in a cohort tend to not to want to pair with
each other. I think the problem of sibling pairings is a long-range
concern involving the overall genetic makeup of the population, and
not a problem in a single isolated case. In reintroductions of small
populations of endangered species, one often has little choice, with
genetics so limited to start with.
(2003) have a brother-sister pair of Whooping Cranes in Florida that
has successfully raised 2 young. If they lay more eggs next year
we would like to substitute an egg from another pair so that that they
raise a youngster with less in-bred genetics. Siblings from the same
nest in different years may just treat a sibling as they would any
Whooping Crane. Sibling pairs would not be good from a genetics standpoint
and would presumably lead to less fitness and lower survival of offspring.
So these types of sibling pairings — if they occurred — would
probably be self-limiting, since those pairs would not be as successful
at breeding and thus their genetic material would eventually be reduced
in the population.
Stehn, Whooping Crane Coordinator
U.S. Fish and Wildlife Service
P.O. Box 100
Austwell, TX 77950
North is pleased to feature this educational adventure made possible
by the Whooping
Crane Eastern Partnership (WCEP).