Western Great Lakes Bird and Bat Observatory

Headquarters at Forest Beach Migratory Preserve

Citizen Science

Meet the Martins

Purple martin JoelTrick 26 April 2017bPurple Martin Photo by Joel Trick

Purple Martins are one of the most beloved birds in North America.  One reason for their popularity is that, at least in the eastern half of the continent, they carry on their lives in man-made birdhouses in our back yards.  Martins are in the Swallow family (Hirundinidae) and they are, at almost 8” long (Cardinal-sized), the largest of our swallows.  They are vocal, swift, agile and handsome, and they astound us with their aerial maneuvering, both feeding and drinking on the fly. 

People also love them because they have “site fidelity,” which means that the birds that hatched in your Martin house last year will likely return, with their parents, this year.  Unlike most other songbirds, they are comfortable nesting shoulder-to-shoulder with other Martins, and they form huge roosting flocks after their chicks are fledged and while on their wintering grounds.  

Throughout their range, Purple Martins (Progne subis) are found near water in open areas, grasslands, parks, dunes, suburbs, etc.  They are cavity nesters; in the eastern part of their range, they’re almost entirely dependent on humans for their housing, but in the West, they nest in dead snags, in holes made by woodpeckers, in other natural cavities along woodland edges and clearings, and even in saguaro cactuses.  The western birds may form small colonies, but pairs will also nest solo.    

The question is, of course, “Where did Purple Martins nest before people started making houses for them?”  From the early 1700s on, European explorers wrote about seeing Martins living in hollowed-out gourds in Indian villages, but by then, Martin houses were also common at farm houses and taverns (Audubon observed that “the handsomer the box, the better does the inn generally prove to be.”).  Did Native Americans teach the newcomers, or vice versa?  We may never know the answer, but no matter who started it, Martins have been using man-made nest sites for a long time. 

Another reason that people like them is that we’ve been told that a Martin may eat as many as 2,000 mosquitoes each day.  In fact, they feed on many kinds of flying insects - beetles, grasshoppers, butterflies and moths, wasps and bees, plus lots of spiders, dragonflies, and damselflies.  Purple Martins catch their prey on the wing, and while they may patrol just above the surface of the water, they also hunt up to heights of 150 feet and more – the highest of the swallow species, and higher than mosquitoes normally fly.  In the southeastern US they scoop up impressive numbers of fire ant queens on the queens’ nuptial flights. 

Purple Martins overwinter in central South America, and they take their time getting there, covering 5,000 miles in four to six weeks.  Older males (“Martin Scouts”) return from their wintering grounds first, followed by older females, and, finally, by last year’s young.  They stake a claim to a few nest sites (because they nest communally, the only territory the eastern birds defend is a compartment or two in a nest box), and the male’s bubbly “dawn song” invites more Martins to join the colony.  They lay three to six eggs, which the male helps incubate (a little) for about 2 ½ weeks.  The young are fledged a month after hatching, but they hang around because their parents continue to feed them.  There’s a single brood per summer in Wisconsin, and most Martins have left the state by September 1. 

Martin populations have been declining over their range, particularly in the West.  Extended wet or cold snaps when insects disappear, removal of dead trees, collisions, pesticides, and competition from other cavity nesters, especially from non-native Starlings and House Sparrows, are all factors. 

Purple Martins are one of a group of birds called “Aerial Insectivores,” many of whose numbers are also decreasing, and the Western Great Lakes Bird and Bat Observatory has been working to raise awareness about their plight. For more information on the Observatory's work, click here.  In Wisconsin, Aerial Insectivores include about 19 species of swallows, swifts, flycatchers, and nightjars (Common Nighthawks, Chuck-will’s-widows and Whip-poor-wills).  What they have in common is that they are fueled by flying insects, and especially by “aeroplankton,” masses of tiny invertebrates that float through the air. 

Entomologist Gilbert Waldbauer did the math in the 1990’s and figured out that on a day in May, a square-mile column of air that starts 20 feet above the surface and stretches up 500 feet will contain 32 million arthropods (and an amazing number of them are spiders!).  He wrote that “This amounts to 6 arthropods per 10 cubic yards of air.”  The density of aeroplankton decreases with altitude and at night – nocturnal insectivores (Whip-poor-wills and Common Nighthawks) hunt for bigger prey, like moths. 

The problem is that researchers are documenting a serious decline in numbers of insects globally, primarily due to climate change and pesticide use.  Simply put, there are fewer morsels of bird food swimming through the water, crawling over the leaves, and flying around in that air column.  Some studies show that in less than 50 years, insect populations have dropped by more than 50%.  As insect populations plummet, so do those of the many species that depend on them (think of all the birds that hunt insects for their nestlings), including bats. 

This is an alarm that has been sounding since the mid-1980’s.  Says Jon McCracken in an article in Birdwatch Canada (2008), “The proverbial clock may well be ticking down on many common species of aerial insectivores in Canada.”  He lists some probable causes – climate-related changes in range or phenology (timing and synchronicity), light pollution, warming water temperatures, and pesticides, especially neonicotinoid pesticides. 

He calls Purple Martins “mid-level” foragers (they mostly hunt for prey above 30 feet from the ground) and says that mid and high-level foragers (60-plus feet) are declining more rapidly than lower foragers and “hawkers” - birds that perch on vegetation and fly out to grab insects. 

For more information about Purple Martins:

https://www.purplemartin.org/

https://blog.nature.org/science/2016/09/12/purple-martins-the-bird-that-relies-on-human-built-nests/

Purple Martin sounds - https://www.audubon.org/field-guide/bird/purple-martin   

On putting up a Martin house - http://www.birdwatching.com/tips/purplemartin_landlord.html

For more information on aerial insectivores:

https://www.bsc-eoc.org/download/BWCwi08.pdf

http://www.ace-eco.org/vol5/iss2/art1/

For more information about aeroplankton: http://www.learner.org/jnorth/tm/spring/Aeroplankton.html

For more information about declining insect numbers:  https://www.nytimes.com/2018/11/27/magazine/insect-apocalypse.html?smid=nytcore-ios-share

RARE STRIPED SADDLEBAG DRAGONFLY AT FOREST BEACH

Article by Kate Redmond


Forest Beach Migratory Preserve was created to be a resting and refueling place for migrating birds as well as a productive habitat for breeding species. It turns out that what’s good for the birds is good for other wildlife, too. A number of rare dragonflies and damselflies have found their way to the preserve, and with more eyes on the place, it’s only a matter of time before others are discovered. Eight of the 42 species on the property list are rare visitors.

Late summer is both a great and a challenging time for dragonfly watching. Great because some of our larger species like darners and saddlebags dominate the air space. Challenging because these dragonflies often fly for a long time without stopping, and when they do rest, they perch vertically, down in the grass or on woody plants. And they’re jumpy; in order to get a picture -- or even a good look at them -- you have to see them before they see you. 

Saddlebags are called saddlebags because of the pigmented area on the wings on either side of the abdomen. Red, Black, and Carolina Saddlebags are in the “broadsaddle” group, so-called because their irregularly shaped saddles are wide. Black Saddlebags are common at Forest Beach from mid-summer on; Red Saddlebags are a little less common; and Carolina Saddlebags, rare visitors to Wisconsin from the eastern and southeastern United States, have been spotted at the preserve fairly regularly. 

On September 11, 2018, I photographed a fourth saddlebags at the preserve, a Striped Saddlebags (Tramea calverti), and two weeks later, I found another one there, a different individual. Striped Saddlebags, named for the conspicuous stripes on the thorax, is a tropical species. Individuals are considered vagrants or accidentals here, not regular migrants. (Only about 15 species of dragonfly are.) As a result, they’re a most-wanted species among dragonfly enthusiasts in Wisconsin. There are small, resident populations in far South Florida and along the United States-Mexico border, but the dragonflies are more at home through Central and South America, the Galapagos, and the Bahamas. The moral of the story is, “If you see a saddlebags with red saddles, look twice.” 

Striped Saddlebags are in the “narrowsaddle” group because the smooth-edged saddles don’t extend very far into their wings. Striped Saddlebags wander farther north than other narrowsaddle saddlebags.

As vagrants, Striped Saddlebags have some big flight years and other years when they stay home, but when they do travel, it’s not uncommon for them to move in small groups. A huge flight occurred in 2010, when an article on the Cape May Bird Observatory’s blog View from the Cape described the area, in New Jersey, as “Swimming in Striped Saddlebags.” Striped Saddlebags also appeared in Michigan, Minnesota, and Ontario. There were widespread sightings in 2012. 

The Wisconsin Odonata Survey lists 19 Striped Saddlebags sightings since the first records in 2012, when it was seen in five counties. Of the 19 sightings, 14 are from four southwestern counties along the Mississippi. Along with the individuals seen at Forest Beach in 2018, Striped Saddlebags were recorded Kenosha County in early September and in La Crosse County in late September. 

The life cycle of a Striped Saddlebags mirrors that of other saddlebags. Females prefer to deposit eggs in shallow, open, fishless ponds with lots of floating vegetation, and the young dragonflies (naiads) live under water, feeding on any aquatic invertebrates that they can tackle. Mature naiads crawl out of the water, often under cover of darkness in order to avoid predators, rest, and then split the back of their exoskeleton and pull their body out. When their wings are fully extended and hardened, the young dragonflies are ready for flight. 

Both male and female Striped Saddlebags were present at Forest Beach in the fall of 2018. Are there naiads waiting for the water to warm in 2019, or would these tropical dragonflies be too sensitive to survive under the ice? Stay tuned.

For more information, see the article “Rare Dragonfly at FBMP” in the Observatory’s May-June 2017 newsletter.

TRUMPETER SWAN: SPECIES NO. 256

By Kate Redmond

When your property list tops 250, the next birds you add tend to be the unexpected species, and that was the case for Forest Beach Migratory Preserve’s 256th species.

In early April, a Trumpeter Swan was spotted on one of the Preserve’s ponds by Waterbird Watch Technician Calvin Brennan, whose usual beat is an observation blind on Lake Michigan at Harrington Beach State Park (http://birdbatclone.ecowebdesign.accountant/what-we-do/waterbird-watch). The swan’s presence celebrates an avian success story.

At four-and-a-half to five-and-a-half feet long, with a wingspread of more than seven feet, and weighing in at 15 to 30 pounds (females are smaller), Trumpeter Swans (Cygnus buccinator) are the largest waterfowl in North America and our heaviest flying bird. The Wisconsin Department of Natural Resources great kids’ website EEK aptly describes them as “a big, beautiful, white bird.”

Trumpeters can be mistaken for our native Tundra Swans (called “Whistling Swans” in older bird books) and for the non-native Mute Swan. Season (we don’t expect to see Tundra Swans in Wisconsin in the summer, but Mute Swans are present), size, posture, and bill color help distinguish the three. For identification tips, see http://www.trumpeterswansociety.org/swan-identification.html. The much-smaller Snow Goose is white, but it has black wing tips, and so does the somewhat-larger White Pelican.

The word buccinator in the Trumpter’s scientific name is Latin for “to trumpet,” and the swan’s call is described as a deep, resonant, and trumpet-like “oh-OH’.’” Swans have a variety of vocalizations that help them to stay in contact with other birds, advertise their territory, and signal alarm (http://www.audubon.org/field-guide/bird/trumpeter-swan). 

Historically, Trumpeter Swans bred from Missouri, Illinois, and Indiana through northern Canada and wintered as far south as Texas. John Lawson, exploring North Carolina in 1701, wrote, “Of the swans we have two sorts, the one we call Trompeters...These are the largest sort we have...when spring comes on they go the Lakes to breed. The sort of Swans called Hoopers; are the least.” Explorers in the Detroit River area of Lake Erie during the same period wrote, "There are such large numbers of swans that the rushes among which they are massed might be taken for lilies.”

In 1933, the known population of Trumpeter Swans in the wild dipped below 70, and concerned wildlife biologists swung into action. Trumpeters had been hunted nearly into extinction for their meat and feathers and for their skin, which was used for powder puffs. They were also harmed by the overhunting of muskrats and beavers, whose dams and lodges provide nest platforms for the birds. In the early 1950s, to the relief of conservationists, a previously unknown Pacific population of a few thousand birds was discovered in Alaska.

Trumpeter Swans, which had not been recorded in Wisconsin since 1937, were listed as a State Endangered Species in 1987. As part of the recovery plan, eggs were collected from nests in Alaska, flown to Wisconsin, and incubated at the Milwaukee Zoo. The young birds were then released after being acclimated to the wild. Wisconsin’s population numbers more than 5,000 today, mainly in our northern and central counties. For a great story about the early days of the Wisconsin recovery effort, see http://www.wisconservation.org/white-trumpeter-swans-make-impressive-comeback/.

Starting in the late 1960s, Trumpeters have been surveyed every five years in the continental United States. The 1968 survey found 2,572 birds; 6,206 were seen in 1980, 18,486 in 2000, and 34,249 in 2010. The most recent count (2015) tallied 63,016 birds, documenting a remarkable comeback. The swans now nest in the upper Midwest and western Great Lakes and in some areas of the Dakotas, the Rockies, and far northwestern North America.

Trump range map

https://www.allaboutbirds.org/guide/Trumpeter_Swan/maps-range

The Miraculous Monarch

Monarchs by KR MonCat by KR

Monarchs by Kate Redmond  

By Kate Redmond

Ecologically speaking, putting almost all of your eggs in one basket is a really bad idea. 

Quick review: Monarch butterflies (Danaus plexippus) feed on a variety of flowers but lay their eggs only on plants in the milkweed family. The bright, aposematic (warning) colors of both the butterfly and its caterpillar alert potential predators to back off. (Poisonous milkweed sap renders the caterpillar toxic, and it carries its toxicity into adulthood.) 

Monarchs migrate. Let’s unpack that simple, two-word sentence, because the biology behind it is complicated (and miraculous), and whole books have been written about it.

There is a Pacific population of Monarchs that migrate only as far as southern California in winter (though some free spirits have wandered as far as Hawaii and beyond), and there are year-round breeding populations in the Florida peninsula and along the Rio Grande. Historically, all of the migratory Monarchs east of the Rockies overwintered on a dozen or so smallish sites in the oyamel fir forests of the Central Highlands northwest of Mexico City. 

Monarchs usually return to Wisconsin by mid-May. Researchers don’t know whether the late migrations recorded in the past few years are random events or are due to climate change. Once they get here, there are several short-lived generations that serve to produce more Monarchs, but in mid-August, a generation is produced that uses its energy to migrate rather than to procreate. This final brood, called the Super-generation or Gen 5 (the fifth generation removed from Mexico), is exceptionally long-lived and is the only generation that is tagged for migration studies. Experiments suggest that “host plant quality” (Monarch caterpillars prefer tender, young leaves, not the leathery plants of late August), decreasing day length, cooler overnight temperatures, and the changing tilt of the earth combine to flip a switch in the Monarch’s brain (which is about the size of the head of a pin). Wherever Monarchs are, they are cued to start moving south when the sun recedes to around 57 degrees above their southern horizon. (They migrate along the shore of Lake Michigan.)    They navigate using an internal “sun compass” that allows them to adjust their orientation in relation to the sun’s movements across the sky, and they probably also sense magnetic fields with their antennae. This allows Monarchs in Michigan, Maine, and Montana to set correct (but different) flight plans for central Mexico. 

The butterflies move south in the fall, spending the winter some 1500 miles south of Wisconsin. Monarchs eat little on their wintering grounds, depending on fat reserves built up during their leisurely migration. (A newly emerged butterfly has about 20 mg of fat in its body, but a Monarch newly arrived in Mexico carries 125 mg of fat.) In spring, signaled by warming temperatures and the availability of milkweed, Monarchs become reproductively ready and head back north, being careful not to outpace the emerging milkweed plants. They lay eggs in the southern tier of states, and their offspring continue the journey.

The spectacle of Monarch butterfly migration is one that inspires international awe (and, not surprisingly, sometimes-invasive ecotourism), and the drastic decline in Monarch numbers over the past decade has resulted in quite an outcry. Some numbers: In the mid-1990s, an estimated one billion Monarchs migrated to central Mexico, with another million counted in California. Today, the entire population is estimated at 56.6 million—a decline of more than 80%. (A 2013 World Wildlife Fund count was 33 million.) During the winter of 1996-97, wintering butterflies covered 21 hectares (one hectare is just under 2.5 acres). In 2013-14, they occupied only two-thirds of one hectare of forest, and 80% of the butterflies were found on just a few sites. Predictions for this year, if all the ducks stay in a row, are more optimistic, but far from rosy.

What’s happening? In a nutshell:  

WEATHER AND CLIMATE:

Monarch survival depends on favorable weather in their summer range, during migration, and on the wintering grounds. The extreme weather events associated with climate change will affect Monarchs negatively—cold, wet winters; a warmer climate in Mexico that may negatively impact the oyamel fir trees; large storms or stubborn frontal systems at the start of the spring migration; and prolonged heat and drought that shorten the blooming periods of flowers (and therefore the availability of nectar), especially in plants that the butterflies depend on during migration. (Remember 2012, when even the prairie plants looked wilted?) 

It’s cold up in the mountains, but wintering Monarchs can tolerate cold temperatures if they’re dry, and they burn fewer calories idling in cool weather. Rain or snow that wets the butterflies, followed by freezing temperatures, are a one-two punch, especially in January and February, when butterfly thoughts are turning northward and their fat supplies are waning. In the winter of 1995, snowstorms on the wintering grounds caused greater than 60% mortality. As the butterflies headed north in the spring of 1996, el Nino delivered heavy rains in the southeastern United States, and more died. In 2002, 2004, and 2010, huge Pacific weather systems brought heavy rain, hail, and frigid air into the wintering areas, decimating the Monarch population. The 2002 storms resulted in a 75% casualty rate.  

HABITAT LOSS:

Although the Mexican government has banned logging in the area, illegal logging continues to nibble away at the oyamel forests, which affects the microclimate created by the trees’ canopy and allows greater temperature fluctuations within the forests. The trees are also threatened by bark beetles. North of the Rio Grande, commercial-urban-suburban development is replacing Monarch habitat at a rate, according to one source, of 2.2 million acres per year (6,000 acres a day). The biofuel movement accounts for some of this loss, with land being taken out of the Conservation Reserve Program to produce corn to make ethanol. The tricky part, of course, is balancing the needs of the Monarchs and the needs of the people who live in the area.  

MILKWEED LOSS:

The Corn Belt produces more than half of the Monarchs that migrate to Mexico. Common milkweed (Asclepias syriaca) is their food of choice, but common milkweed is disappearing, largely due to today’s agricultural practices. Crops like corn and soybeans are genetically modified so that they can survive exposure to herbicides like Roundup, allowing farmers to spray more often. (Crops are in the works that will have multiple resistances.) Sprayed chemicals often drift past the borders of agricultural fields, and roadside flowers become collateral damage. Neonicotinoid insecticides kill agricultural pests, but innocent bystanders are also exposed to this neurotoxin when they nectar on adjacent wildflowers. 

The clean farming trend that advocates removing fence rows and non-agricultural vegetation between cultivated fields leads to the loss of native plants and wildlife, and roadside mowing takes a toll, too. Milkweed is slow to regenerate, and one study suggests that 60% of milkweed has been eliminated from the grassland ecosystem in the Midwest (http://www.mlmp.org/results/findings/pleasants_and_oberhauser_2012_milkweed_loss_in_ag_fields.pdf). The tricky part, of course, is balancing the needs of the Monarchs against our desire for inexpensive food.

OE:

Ophryocystis elektroscirrha (OE) (http://monarchparasites.uga.edu/whatisOE/) is a protozoan parasite that infects only Monarchs and the related Queen butterflies. One theory is that Monarchs pick up the protozoan from the leaves of tropical milkweeds that don’t die back in the winter and so have a longer period to harbor the parasite and its spores. Female Monarchs pass it on to their eggs and to the plants they land on, and caterpillars ingest it as they feed. Most of the damage is done during pupation, and emerging adults are covered with spores. Infected adults may simply be less fit (the long migration south is Darwinian natural selection in action), but a heavily infested Monarch may have difficulty emerging from its chrysalis and may have deformed wings. OE was first noted in South Florida and has been around for almost 50 years, and although it’s been found in all of the populations of Monarchs, the highest rates of infection are found in non-migratory groups (reaching 70% in South Florida). The infection rate in eastern migratory Monarchs is between 7% and 8%.  

PREDICTIONS:

There were three hurricanes and two tropical storms at the start of the 2017 fall migration period https://monarchwatch.org/blog/2017/09/15/forgotten-victims-of-harvey-the-pollinators/.. The fall migration of 2017 along the Atlantic Coast was late, with some butterflies lingering into late October and even early November, lulled by unseasonably warm weather, the late migrants left susceptible to storms and freezes.  

Chip Taylor at Monarch Watch (https://monarchwatch.org/) issues frequent updates about Monarch populations. As of March 18, World Wildlife Fund Mexico in collaboration with CONANP and the Monarch Butterfly Biosphere Reserve, announced the total forest area occupied by overwintering Monarch colonies. Nine colonies were located, with a total area of 2.48 hectares, a 14.77% decrease from the previous season. 

He also says, “we need a comprehensive plan on how to manage the fragmented edges and marginal areas created by development and agriculture since it is these edges that support Monarchs, many of our pollinators, and the many forms of wildlife that are sustained by the seeds, fruits, nuts, berries, and foliage that result from pollination.”  

POSITIVES:

The plight of the Monarch has energized people and organizations across the country. The Monarch Butterfly Biosphere Reserve, which contains most of the overwintering sites, was created in 1980 and declared a World Heritage Site in 2008. The International Union for Conservation of Nature declared Monarch migration as a Threatened Phenomenon, and the US Fish and Wildlife Service is considering adding Monarchs to the Endangered Species list. Monarchs are expected to benefit from the 1,500-mile-long “Butterfly Highway” proposed by President Obama as part of his efforts to help native pollinators (http://www.csmonitor.com/Environment/2015/0522/How-Obama-s-butterfly-highway-paves-way-to-save-embattled-monarchs). 

The Monarch’s population plunge has been publicized by (among others) the National Wildlife Federation, the Defenders of Wildlife, the Xerces Society, World Wildlife Foundation, USDA Natural Resources Conservation Service, the Natural Resources Defense Council (suing the EPA over pesticide regulations), and a whole bunch of newspapers and periodicals. The US Fish and Wildlife Service is committing $20 million for habitat restoration over five years. The Monarch Joint Venture (http://www.monarchjointventure.org/) is a partnership of federal and state agencies, non-governmental organizations, and academic programs working together to support and coordinate efforts to protect the Monarch migration across the lower 48 United States. And there are many grassroots organizations. 

WHAT YOU CAN DO (among other things):

* Plant native milkweed. (You’ll be able to choose from three native species at our plant sale during our World Migratory Bird Day celebration.)

* Plant flowers for butterflies to nectar on. (At our plant sale, we’ll also be selling native nectar plants that adult Monarchs rely on.)

* Join the growing number of people who collect Monarch eggs from vulnerable locations (like the paths of mowers) and raise them indoors for release (instructions on-line).

* Refrain from celebrating a birth or death by releasing commercially raised butterflies.

* Be ultra-cautious in your use of pesticides.

  * And be a citizen scientist—that is, add your observations of eggs and adults to the data at Monarch Watch (http://www.monarchwatch.org/) and/or the Monarch Larva Monitoring Project (http://www.mlmp.org/).

Such a fragile balance. "The Monarch butterfly unites the three countries of North America in peace. It is an ambassador of peace which requires protected areas and ecosystems that are preserved through sustainable agricultural and forestry practices. Let us continue to work together to maintain a healthy and balanced ecosystem for all North America."—President Jimmy Carter

FOR MORE INFORMATION:

http://www.xerces.org/monarchs/

https://www.learner.org/jnorth/tm/monarch/conservation_overview.html

http://www.npr.org/2015/03/04/390757757/monarch-butterfly-population-rejuvenated-after-last-years-record-low

http://www.washingtonpost.com/blogs/wonkblog/wp/2014/01/29/the-monarch-butterfly-population-just-hit-a-record-low-heres-why/

http://www.learner.org/jnorth/monarch/News.html

http://www.xerces.org/wp-content/uploads/2014/10/PartnershipsforMonarchs_web.pdf