Whooping cranes are critically endangered and exist in a
single natural migratory population in the wild. This
population spends the summer in Canada and winters along the Texas
Gulf Coast. The number of whoopers has increased from a fewer than
20 in 1941 to a current estimate of 304 individuals, but the
population remains at risk. A natural disaster or disease outbreak
could have a major impact on the crane population, so it is
important to learn which disease agents currently infect crane
populations. We use non-invasive sampling approaches (i.e.,
collection of freshly voided fecal samples from the refuge) and
classical and molecular parasitology techniques to characterize the
parasite communities that infect the wild whoopers as a first step
in determining which parasites may impact population growth.
Sandhill cranes are closely related to whooping cranes. Sandhill
cranes share habitat and migration routes with whooping cranes, so
they are likely exposed to the same diseases. Through partnering
with hunters and field biologists, we perform field necropsies
hunter-harvested sandhill cranes to search for visible signs of
disease and take samples of all the organs and blood to test for a
number of parasites, viruses, and toxins. In doing so, we are
evaluating the sandhill crane as a surrogate species for the
whooping crane for understanding population-level infection.
Surrogate species can be very useful in endangered species research
because sample sizes are, by definition, very limited when working
with a species of conservation concern.
After
two winter seasons of sampling, we found that almost 30% of
whooping crane fecal samples are positive for a protozoan parasite
called coccidia. This is an important finding because the same
species of coccidia has caused severe disease and death in captive
crane chicks, and may be impacting population growth in the
wild. The most common 
parasitic worm we have found in sandhill cranes is a
fluke infecting the trachea in over 40% of sandhill cranes. We have
also detected protozoan blood parasites in almost 60% of whooping
cranes and sandhill cranes; these parasites are spread by
blood-sucking vectors. Once we obtain the genetic signatures of
these parasites, we can link them to similar parasites that cause
disease in other populations of wild birds.
In collaboration with the Schubot Center, Department of Poultry
Science, Department of Entomology, Department of Veterinary
Integrative Biosciences, Texas Parks and Wildlife Department, USGS
Patuxent Wildlife Research Center, and the International Crane
Foundation, we are currently sequencing the genome and
transcriptome of the whooping crane and sandhill crane. Once
analyzed, the genomes will be freely available to researchers and
will provide a background for further understanding crane health
and disease.
We aim to use our data to assist in whooping crane conservation
and sandhill crane management so future generations can continue to
enjoy these magnificent birds. We greatly appreciate financial
support from the United States Fish and Wildlife Service, Region 2,
Division of Migratory Birds- Avian Health and Disease Program;
American Association of Zoo Veterinarians- Wild Animal Health Fund;
The Cooper Ornithological Society; and the Schubot Center.
