Up four flights of stairs and in a remote corner of Brookfield Zoo’s Tropic World, a version of "The Bachelorette" TV show is unfolding.
This one features a tropical bird, the female blue-gray tanager, perched in a large enclosure. Lining one side of her cage are three separate enclosures. Each contains a male tanager who can see the female but is blocked by wire mesh from having conjugal relations with her. Cameras are trained on the scene for hours a day.
Whichever male she spends the most time in front of will become her mate. No romantic rendezvous in an Argentine vineyard or stroll through a floating market in Thailand. No red rose.
This is scientific research, but the vagaries of romance are in the air, too. So is the hope that the research could revolutionize breeding practices of many species at institutions around the world and help resolve one of zoos’ biggest challenges: sustaining their populations.
Bird breeding research Antonio Perez / Chicago Tribune
A caged female blue-gray tanager, left, rests on a perch as one of three male tanagers appears at the right, during a pairing experiment in which she will "choose" from three male birds in separate cages, Monday, Feb. 6, 2017, at Brookfield Zoo.
A caged female blue-gray tanager, left, rests on a perch as one of three male tanagers appears at the right, during a pairing experiment in which she will "choose" from three male birds in separate cages, Monday, Feb. 6, 2017, at Brookfield Zoo.
(Antonio Perez / Chicago Tribune)
"By taking this different approach, what we’re looking at is trying to increase the welfare of the animals and their breeding success," said Tim Snyder, curator of birds for the Chicago Zoological Society, which runs Brookfield. He stood in the zoo’s Feathers and Scales exhibit one Monday morning. Tropical birds flitted overhead. Exotic calls filled the air.
The bigger idea, Snyder and Chicago Zoological Society Senior Director of Animal Welfare Research Lance Miller said, is to use techniques distilled from the bird bachelorette experience to develop a strategy that could be extended to all birds, reptiles, mammals and other animals in captivity.
Kevin McGowan, an ornithologist at the Cornell Laboratory of Ornithology, where he focuses on the social behavior of birds, said he appreciates that thinking. He also recognizes the less scientific component of the research.
"We’re all in favor of true love," said McGowan, who is not involved in the research. "Anything we can do to promote true love among birds, especially around Valentine’s Day, is a good thing."
Bird breeding research Antonio Perez / Chicago Tribune
Lance J. Miller, Ph.D., Senior Director of Animal Welfare Research at Brookfield Zoo, looks over a single cage for a female blue-gray tanager bird and her three separated cages for three male birds in a pairing experiment at Brookfield Zoo, Monday, Feb. 6, 2017.
Lance J. Miller, Ph.D., Senior Director of Animal Welfare Research at Brookfield Zoo, looks over a single cage for a female blue-gray tanager bird and her three separated cages for three male birds in a pairing experiment at Brookfield Zoo, Monday, Feb. 6, 2017.
(Antonio Perez / Chicago Tribune)
In the wild, female birds generally choose their mates after courtship displays from both sexes, but it’s unclear exactly what traits the females like, McGowan said.
Sometimes choice seems based on appearance — perhaps a longer tail, bigger crest or brighter colors, he said. The viability of nesting in an area a male has staked out also seems to play a role, McGowan said.
At zoos and similar institutions, almost all animal breeding, including that for birds, is based in science and crunched numbers. Experts review genetic data, enter it into a database then use software to come up with the best pairings that will preserve genetic diversity.
It is the animal equivalent of an arranged marriage and is very efficient.
But chemistry is not part of the equation. And laboratory research with rodents suggests that giving the female more of a choice could be a natural way to maintain genetic diversity while increasing pregnancy rates, litter sizes and offspring survival. Other research with Gouldian finches indicated that females in arranged pairs with males showed increased stress and compromised reproduction.
Bird breeding research Antonio Perez / Chicago Tribune
Animal Welfare Research Department volunteer Kristie Charmoy looks over hours of video clips showing how a female blue gray tanager female bird interacts with three male blue gray tanagers at Brookfield Zoo, Monday, Feb. 6, 2017. Brookfield Zoo just started a five- to six-month study that will allow two bird species to chose their mates via a format that resembles the "Dating Game."
Animal Welfare Research Department volunteer Kristie Charmoy looks over hours of video clips showing how a female blue gray tanager female bird interacts with three male blue gray tanagers at Brookfield Zoo, Monday, Feb. 6, 2017. Brookfield Zoo just started a five- to six-month study that will allow two bird species to chose their mates via a format that resembles the "Dating Game."
(Antonio Perez / Chicago Tribune)
In his proposal to obtain funding for the research, Miller wrote that allowing animals to choose their mates may yield greater compatibility, which could lead to "improved parental care."
All those factors could combine to yield solutions to the challenge of sustaining populations in zoos and aquariums, a problem that the Association of Zoos & Aquariums tracks back to a lack of animal space in the institutions and one that was highlighted in a 2011 report for the World Association of Zoos and Aquariums.
The report found that about 40 percent of "cooperatively managed populations" in association institutions had decreased in five years. A total of 34 percent of the bird populations had dropped in that time, the report stated.
A report by the association one year later made a similarly dire prediction.
Bird breeding research Antonio Perez / Chicago Tribune
Animal Welfare Research Department volunteer Kristie Charmoy looks over hours of video clips showing how a female blue gray tanager female bird interacts with three male blue gray tanagers at Brookfield Zoo, Monday, Feb. 6, 2017.
Animal Welfare Research Department volunteer Kristie Charmoy looks over hours of video clips showing how a female blue gray tanager female bird interacts with three male blue gray tanagers at Brookfield Zoo, Monday, Feb. 6, 2017.
(Antonio Perez / Chicago Tribune)
"Unless a group of zoos is deeply committed to a given species, including sharing the specialized space required for breeding, rearing young, recruitment, dispersal and, of course, caring for the old and feeble, it will become impossible to achieve demographic and genetic viability," the report, "Where Will Zoo Animals Come From?" stated.
One effort to address the issue is the Conservation Centers for Species Survival, a consortium of five organizations that together manage more than 25,000 acres for endangered species study, management and restoration. Established in 2005, the centers are conducting research on cheetahs that resembles Brookfield’s work with birds.
Also, the Population Management Center, which helps zoos across the U.S. by providing demographic and genetic analyses of animalsas well as breeding and transfer plans, among other services, is based at Lincoln Park Zoo.
In addition to blue-gray tanagers, Brookfield’s six-month study includes red-capped cardinals. Both species are abundant and found in northern regions of South America and, in the case of the tanager, in Central America, as well. Miller said the project, funded by the Association of Zoos & Aquariums, Chicago Zoological Society-Brookfield Zoo and the St. Louis Zoo, "will easily be over $100,000."
A total of 50 birds divided evenly between both species will be used. Five females from each species will be fitted with radio frequency leg bands and have their locations tracked over five days. Once the females make their choice and are paired with males, their behavior and that of those genetically matched couples will be monitored by video.
Rare birds spotted around Lake County because of Migratory Bird Treaty Sheryl DeVore
Danny Diaz recently found three American avocets and willets — rare migratory shorebirds — at the Lake Michigan shoreline in Waukegan.
When Libertyville resident Andy Stewart learned of the sighting, he went to the beach and found the willets — but the avocets were gone. Stewart later searched…
Danny Diaz recently found three American avocets and willets — rare migratory shorebirds — at the Lake Michigan shoreline in Waukegan.
When Libertyville resident Andy Stewart learned of the sighting, he went to the beach and found the willets — but the avocets were gone. Stewart later searched…
(Sheryl DeVore)
Researchers also will count the number of eggs laid and hatched as well as the number of nestlings that reach fledgling age — a critical sign of reproductive success. In addition, they will examine female fecal samples for hormones that indicate stress levels. Pairs will be maintained for the entire six-month breeding season, during which each species typically lays two clutches.
By the time it ends and all the data and observations are processed, Miller and Snyder should have an indication of what effect female choice has on bird species sustainability, maybe some insight into the mystery of attraction and perhaps the key to solving a stubborn problem facing zoos.
"What I really like about this project," Miller said, "is it’s using science to help animal management. Any time we can use science to better understand animal care and provide high levels of animal welfare, that’s ultimately going to be in our best interest."
tgregory@chicagotribune.com
Twitter @tgregoryreports
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