Local Conservation Efforts
Great Lakes Piping Plovers
Piping plovers are tiny shorebirds that make shallow nests in the summer on flat, open, sandy beaches in northern Michigan – the same beaches that attract people, their pets and development.
In 1986 there were only 17 nesting pairs of this endangered species remaining in the Great Lakes, and a federal recovery program was established by the United States Fish and Wildlife Service (USFWS). Scientists found that some of the plovers were abandoning their eggs, and they realized that salvaging these abandoned eggs could contribute significantly to the species’ recovery. Because of the Detroit Zoo’s expertise in bird care and incubation, we coordinate a captive breeding program to hatch out abandoned eggs and rear the tiny chicks until they can be released to join wild plovers. This “salvage rearing” is an important part of the federal recovery program for piping plovers.
Abandoned eggs are brought to a captive rearing facility at the University of Michigan’s Biological Station in Pellston, MI. Detroit Zoo curators oversee the incubation and rearing programs and coordinate the involvement of bird care staff from zoos across the country, who help monitor the eggs and care for the chicks after they hatch. The chicks are reared in pens on the beach to protect them from predators as they acclimate to living in the wild.
Piping plovers are able to fly by the time they’re four weeks old, and at that point they’re released at sites with adult plovers and their nearly-grown chicks. They quickly acclimate into these groups and join them for the fall migration to the southern U.S., where they will spend the winter.
The Great Lakes population of piping plovers is now about 60 breeding pairs. The captive-reared birds and their descendants have made a significant contribution to this small population.
The Detroit Zoo’s piping plover program was recognized by the AZA with a significant achievement award for North American conservation in 2009.
Karner Blue Butterflies
The Karner blue is a small butterfly with a wingspan of about one inch. Once widespread from Minnesota to Maine, it now occurs only in isolated pockets in its range. The main reason: a severe reduction in the range and availability of lupine, the butterfly’s host plant, due to fire suppression and habitat destruction for agricultural, residential and other development. Historically, naturally occurring fires maintained the lupine’s open-canopy oak savanna habitat, but the suppression of fire on these lands allowed the development of habitat which is not suitable for lupine.
Since 2005, the Zoo has worked to restore the Petersburg State Game Area in southwest Michigan to more hospitable habitat for lupine and eventually the Karner blue butterfly. The Zoo worked with the Michigan Department of Natural Resources to improve the habitat, which required physically removing invasive plants, performing controlled burns and planting lupine.
Female butterflies are collected in early spring from Allegan State Game Area and brought to the Zoo, where they lay their eggs on lupine plants in a special off-exhibit greenhouse. Once the eggs hatch, the caterpillars are nurtured until they metamorphose into butterflies. The adult Karner blues are then taken to Petersburg and released.
The Zoo plans call for the continued release of Zoo-born butterflies into the wild over the next three to five years. Zoo staff and volunteers will monitor the population at the release site annually until the federal recovery plan goal of at least 3,000 individual butterflies is achieved.
The Zoo has worked with the Michigan Department of Natural Resources (DNR) and Michigan State University’s Kellogg Biological Station since 1985 to reintroduce trumpeter swans to northern Michigan. More than 60 trumpeter swan cygnets hatched in the wetlands near the National Amphibian Conservation Center (NACC) and on the Zoo’s Pierson Lake have been released at sites in northern Michigan.
The Detroit Zoo has helped to reestablish ospreys, fish-eating birds-of-prey, in southeast Michigan. Working with the DNR and the Huron Clinton Metropark Authority (HCMA), osprey chicks from northern Michigan have been transferred to southeast Michigan’s Kensington and Stony Creek Metroparks to establish osprey populations in these areas.
Five-week-old male chicks from northern Michigan are taken from the nests in which they hatched to large enclosed boxes (called hacking towers) in Kensington and Stony Creek Metroparks. Males are selected because they normally return to their fledging sites as adults to nest and rear offspring. Zoo staff provide the transplanted chicks with food, water, medical care and ample space to exercise their wings – until they are ready to begin to fly. As they near this fledging stage, the box is opened and they quickly learn to fly and to catch fish. The young ospreys migrate to South America in the fall of their first year, and after two or three years return to the place they fledged, with a mate in tow, to nest and rear offspring.
A male released in Kensington Metropark in 2000 returned to Kensington in 2002 with a female mate he found during his migration. This pair built a nest within 100 yards of the tower from which he “hacked”, and produced a chick in 2002, kicking off a successful repopulation of ospreys in southeast Michigan. Eighty-seven ospreys have been successfully “hacked”, and by 2008 there were nearly 20 nesting pairs in southeast Michigan, so transplanting ospreys from other areas is no longer part of the project. Zoo staff continue to work with Osprey Watch of Southeast Michigan to gather data on chicks hatched in the area and assist with banding chicks, monitoring their health, and conducting DNA testing to determine the sex of chicks.
National Amphibian Conservation Center staff conduct “catch and release” surveys of mudpuppies, Michigan’s largest aquatic salamander, in the Detroit River near Belle Isle to monitor populations and better detect declines. Mudpuppies are measured, weighed and implanted with computer chips for identification before being returned to the river. While not a threatened species, mudpuppies, like other amphibians, are good environmental indicators of pollution and other potentially detrimental conditions and knowledge of their abundance and population trends will help us learn more about the health of the Detroit River.
One of the Zoo’s newest conservation projects is the rehabilitation of the common tern nesting habitat on Belle Isle. As recently as the 1960s, common terns nested by the thousands on islands in the Detroit River. Since then, habitat loss, nesting disturbances and competition from gulls have caused a significant population decline. Only two nesting colonies remain on the Detroit River, both at the Grosse Isle bridges.
The Zoo has partnered with the Detroit Water and Sewage Department (DWSD) and the Detroit River International Wildlife Refuge to develop a tern nesting site on the east end of Belle Isle on a spit of land owned by DWSD. Common terns prefer nesting on areas with a gravel substrate and a small amount of low vegetation. The Zoo and other partners removed tall trees and added gravel to the Belle Isle site, returning it to a more suitable tern habitat. To make it even more attractive, tern decoys have been placed in the area recorded tern calls are played on speakers in the nesting site. If all goes well, the terns will like the area and build nests on Belle Isle for the first time in many years.
Blanchard’s Cricket Frogs
The tiny Blanchard's cricket frog is an amphibian of special concern in Michigan, with fewer than 30 known wild populations statewide. The species is nearly gone from southeastern Michigan, with just three “natural” populations remaining in the area, two of which resulted from Detroit Zoo translocation efforts.
Those began in 2004, after a University of Michigan graduate student discovered a wild population living in an Ypsilanti Township habitat slated for the construction of condominiums. With approval from the DNR, NACC staff and volunteers collected 1,010 Blanchard’s cricket frogs and tadpoles from the site over two months. The Zoo consulted with the DNR to determine the best locations for the frogs’ release, and after testing and quarantine in the Zoo’s Animal Health Complex, they were released in three sites – including 449 in the wetlands around the NACC.
While their miniscule size – adults are normally between ½ and 1½ inches long – makes them challenging to spot, visitors in late spring to early summer can listen for their distinctive breeding call, sometimes described as the sound of steel marbles clicking together.
Eastern Massasauga Rattlesnakes
The Eastern massasauga rattlesnake, Michigan’s only venomous reptile, is considered a “species of special concern” by the DNR and is protected by state law. The snakes are becoming rare in many parts of their former range throughout the Great Lakes area, primarily due to habitat loss and persecution by humans.
The Zoo participates in the Association of Zoos and Aquarium (AZA) Massasauga Species Survival Plan (SSP), and massasaugas currently live in the Holden Museum of Living Reptiles, where nine young snakes were born last year. Captive-born snakes both help to maintain an assurance population of massasaugas, and also contribute to reintroduction or “head-start” programs in areas where suitable safe habitat occurs.
Working with the Massasauga SSP, the Detroit Zoo contributes to field work with a population of massasaugas in southwest Michigan to determine abundance and establish a long-term monitoring program. The project will also develop methods of population monitoring and management that can be applied to other populations in Michigan and surrounding states.
Because some people fear snakes, efforts to conserve massasaugas include a strong education component. The Zoo helped develop information to correct misconceptions about the species for brochures and posters available at nature centers and other locations in Michigan, Wisconsin and Ontario, including at the Zoo. While they are a venomous snake, massasaugas’ venom isn’t nearly as potent as some of the southern rattlesnakes in the United States, and they don’t pose a serious threat to human life.