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Where Have All The Zoo Birds Gone?
By Laurel Holliday
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Isn't that way too many dead birds?
"I oversee that facility," says Woodland Park Zoo's General Curator Bruce Bohmke, "and my specialty happens to be birds. I think we're in the ballpark with regard to mortality, compared to other zoos."
Jeff Sailer, Curator of Birds at the Miami Metro Zoo, says Bohmke is probably right. "That kind of mortality is not abnormal in a mixed-species zoo aviary."
"The more critters you put in a cage, the more dominance and aggression you have that leads to mortality," says a zookeeper who, until recently, worked at Woodland Park Zoo. Like several other zookeepers quoted for this article, this person does not want to be identified. "There's always going to be a low man on the totem pole."
"Mixed species exhibits aren't always best for birds," Sailer says. "But it's what the public wants."
Troupial. Agnes Overbaugh photo. |
"I was suspicious that some of the mortalities were because of rats," says Janis Joslin, Senior Veterinarian at the zoo. "When the rats are moving around at night, you can hear them rustling in the planters. The birds normally wouldn't fly at night. Rats may have disturbed them and caused them to fly into impediments and hurt themselves. But there's no way to prove it."
On the recommendation of Dave Powell, the zoo's fulltime licensed pest control operator for many years, the Tropical Rain Forest exhibit was closed and emptied of birds several times for a period of weeks--one time for months--while he sprayed insecticides throughout the exhibit and then continuously set out poisonous rat bait.
Over the years, he has spent hundreds of hours applying 24 pesticides to the Tropical Rain Forest, trying to control the rodent, roach, and ant problems. In addition to chemicals, he and all the Tropical Rain Forest keepers have continuously plugged up cracks and holes that served as rat entry points to the building, using silicon caulking, steel wool, or whatever else came to hand.
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Some rat species are tunnelers, and zookeepers contend that they were able to enter the exhibit through the dirt floor, a feature of the original design which was intended to allow for the growth of large trees.
A former keeper in the exhibit says, "The design flaw I see in the building is that you have a dirt floor that goes all the way down to China."
But Bohmke says, "having no foundation is not necessarily a problem. I've seen dozens of exhibits like this throughout the country. It's no worse than many."
Another design feature of the aviary, which zoo staffers say was grand in theory but problematic in practice, is the so-called "living wall," a two-story-tall wall of dirt and plants which forms one side of the domed aviary.
"A lot of the rodents hang out in the living wall," says a former Tropical Rain Forest keeper. "Baby birds get stuck in it, and an opportunistic rat perches there and waits. And kills! Birds lay eggs in there and sometimes they rot."
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The "living wall" is a hazard for people as well as birds. Keepers complain that it's nearly impossible to get a ladder onto it to clean out all the debris that collects in it.
"I think there are some design elements that could be done differently," says Dr. Joslin. "It's hard to put a ladder up there and secure the ladder."
In fact, Joslin says Powell broke his leg when he leaned a ladder against the living wall and it slipped out from under him.
Not only have there been problems with the "living wall" and numerous cracks and holes throughout the exhibit; the roof leaks in parts of the building.
"It's a flat roof," explains Dr. Joslin.
So, who came up with the idea of a flat roof for a building in western Washington? Who failed to figure out how keepers could safely maintain a "living wall"? And why was an exhibit built so that rats could so easily gain access to it?
"We've done remedial work on doors," says Bohmke. "And holes here and there. It's hard to say about whether or not this was poor construction."
The Portico Group, Seattle-based designers of zoo exhibits, museums, aquaria, and botanical gardens, received prestigious awards for the design of the Tropical Rain Forest exhibit. Perhaps that is among the reasons that the Woodland Park Zoo Society Board of Directors recently approved Portico's bid to design the new $4.4 million jaguar exhibit without discussion of the shortcomings of their Tropical Rain Forest design.
Better Living Through Chemistry?
Since the Tropical Rain Forest opened in 1992, chemicals have been applied to it by the gallons to control rats, mice, roaches, and ants. Bohmke is adamant that none of them were harmful to birds or people. "They're very safe compounds," he says.
But Dr. Joslin says that a rodenticide called Talon did kill some birds. "It was a brand new product. At the time, the Material Safety Data Sheet indicated that there was no risk of secondary toxicity. We were using this product for mice. Birds were seen eating the mice. And the birds died soon after. We sent in the tissues to the company, and they were able to find the product. So this was a definite cause of death. It was tragic that it happened that way."
If one product used in the exhibit has proven not to be safe for birds, could there be others?
There are ten insecticides currently being used in the Tropical Rain Forest exhibit, according to Dr. Joslin, who says that her insecticide of choice now is Tempo, the brand name of a synthetic pyrethroid called cyfluthrin.
A neurotoxin that acts similarly to the insecticide DDT, cyfluthrin can cause eye, skin, respiratory, and gastrointestinal problems for humans, according to its manufacturer, Miles, Inc. Miles, Inc. also warns that Tempo acts as a carcinogen because it contains crystalline silica which causes increases in lung cancer in laboratory animals and humans who are exposed to it over a period of time.
In addition to the human health hazards of cyfluthrin, the manufacturer warns that it should not be released into streams or the sewer system. "Avoid contaminating environment," says the Material Safety Data Sheet for this chemical. Pyrethroids are highly toxic to bees and spiders and to many aquatic organisms, including fish, at levels that are used to kill the insects that are the target of its application.
Dr. Joslin lists Maxforce G and Avert Gel as two other products she has approved for use in the Tropical Rainforest exhibit. The EPA says of the active ingredient in both of these products, hydramethylnon: "The Cancer Peer Review Committee determined that hydramethylnon should be classified as a Group C carcinogen, a possible human carcinogen, based upon statistically significant lung adenomas and carcinomas."
"A Myth"
Tropical Rain Forest keepers' recorded observations of traumatic bird deaths can be painful to read: "All that was left was bones and matted feathers ... Found dead in pool, very smelly ... Found dead, hanging upside down in the large palm ... Head appears to have been twisted off by another bird ... Found dead on the boardwalk, decapitated and mangled."
Despite many reports of violent bird deaths, "Unknown" is the most common cause of death listed in bird records. Could pesticides have been one of the "unknown" causes of death? It's impossible to say without an in-depth scientific investigation. But it is highly likely that birds forced to live in an enclosure that is constantly doused with chemicals, and in which they are subject to aggression from predators and other birds, do not survive as long as they could have in the wild.
Disheartened by the high rate of bird deaths in the Tropical Rain Forest exhibit, a Woodland Park zookeeper says, "The public has the illusion that by putting animals in zoos, you're making them safer. That's a myth!"
Is There an Upside to This Story?
Zoo records indicate that the number of deaths in the Tropical Rain Forest exhibit is declining, in general (although there were more mortalities in 2001 than in 2000). This could be in large part explained by the fact that, of the 270 birds who have lived there at various times since the exhibit opened, only about 60 birds are currently housed there. The rest have died, been donated or sold to other zoos, or sold to private bird dealers throughout the country.
A freelance writer and photographer in Fremont, Laurel Holliday is a contributing writer for The Seattle Press.
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| Geri Vincent | Apr 12, 2002 | Monroe, WA | Miracle Horse Foundation |
| A concise peek at the lives of those who live at the zoo. A reality of life for Birds and all other species housed in zoos is chronic stress. The fortunate die during capture, the balance suffer through captivity. In spite of the best efforts by committed zoo keepers to provide an adequate life the bottom line is money.The Zoo Society's focus is: what keeps folks coming through the gates? The concept appears to be: sacrifice of a "few" for the betterment of all. Perhaps a reporter might next ask for an accounting of monies that are actually spent on habitat protection and preservation of creatures in the wild. | |||
