How Birds Perform Amazing Migratory Feats—and the Mysteries That Remain
Migrating birds employ skills far beyond human abilities. They depart on time without the use of a calendar and navigate long distances sans smartphone. They fly for days with few, if any, pit stops. Scientists can explain a lot about these arduous journeys, but the quest to fully understand them continues.
How do birds prepare their bodies for flight?
Migrating is a major physical challenge. To get ready for the trip, birds can make huge changes to their bodies in a matter of days. Birds rely on fat to fuel flight, in contrast to humans who burn a lot of carbohydrates and sugars during exercise. Some will double their body weight beforehand by gorging on berries, insects, or mollusks. Others pump up the size of their flight muscles, increase their metabolism, and even grow or shrink their digestive organs to pack on or shed weight.
In a study of Gray Catbirds, for example, University of Rhode Island physiologist and ecologist Kristen DeMoranville found the birds’ flight muscles were larger during fall migration than in summer. And while the birds wintered and rested in the tropics, their hearts shrank in size, and they gained fat, perhaps anticipating the next migration season.
Scientists like DeMoranville are working to understand what genes and proteins are responsible for these body-morphing abilities, using findings from human medical research as a starting point. The results could signal which foods are crucial for birds’ journeys, which in turn could help conservationists identify and protect the most important sources for nutrition.
How do birds know when to migrate?
Even captive migratory birds get restless in fall and spring when they’d normally embark. Varied cues help birds decide when to start their journeys, says University of South Carolina ornithologist Nathan Senner, including day length, temperature, rainfall, food availability, and body condition. Birds may also pay attention to others, using social cues to decide when it’s time to leave.
How birds are using this information—and how much they can change their behavior based on what they are sensing—is less clear, says Senner. Researchers are also curious about how juvenile birds work out their migratory schedule when they’ve never made the journey before.
Studies of the European Nightjar show how a bird’s migratory timing can be finely tuned to its fueling needs. Susanne Åkesson, an evolutionary ecologist at Lund University in Sweden, and her colleagues found that nocturnal nightjars hunt more actively on bright, moonlit nights and are also more likely to start migrating after a full moon than a new moon. After gorging for days, as if at a brightly lit buffet, they’re fueled up and ready to take off.
How do migrating birds find their way?
Any animal, be it a bird, shark, or human, needs both a “compass” and a “map” to know where it is and where it is going. Birds can sense which direction they are flying based on the position of the sun, the stars, and Earth’s magnetic field. Artificially changing the magnetic field around a captured migratory bird, for example, can cause it to fly in the wrong direction, says Nikita Chernetsov, an ornithologist at the Zoological Institute Russian Academy of Sciences in St. Petersburg, Russia.
“The map has been much more controversial,” says Richard Holland, a sensory biologist at Bangor University. Here magnetic fields probably play a role, too. Each spot on the Earth’s surface has a unique magnetic signature based on its position relative to the North and South Poles, which birds seem to be able to sense. Research suggests smell may also be important, says Holland: When scientists have suppressed this sense in some species, experiments show that birds can’t find their way as precisely. But scientists don’t know exactly which smells, whether vegetation or sea spray or even air pollution, these birds rely on as a guide. Identifying the biology underlying these navigational abilities—like where magnetic sensors are located in a bird’s body and what genes code for migratory direction—is a major focus of ongoing research.
In addition to these innate abilities, some navigational skills are partly learned. Adult White-crowned Sparrows captured in the western United States and released in the eastern part of the country will find their way back to their usual migratory route, says Holland, who has tracked the birds. Young sparrows, however, will start migrating south, but don’t know to backtrack west, so they end up in the wrong place. In essence, although their internal migrating compass is inherited, how exactly to reach their wintering grounds is learned by doing.
How do birds sleep on long migratory flights?
Some birds take breaks during trips to rest and refuel. Others fly for days, crossing lakes, oceans, mountains, and continents without stopping. Scientists know it is possible for birds to sleep while flying, but don’t know how much sleep different migrating species are actually catching on the wing. Proof birds can catch in-flight z’s comes from tracking Great Frigatebirds, seabirds that can forage over the open ocean for weeks without landing. The frigatebirds would typically rest half their brain at a time, with one eye closed, while gliding upward on spiraling air currents.
Just because birds can sleep while flying doesn’t mean they do. “We have good reason to think some birds might just not sleep at all during flight,” says Niels Rattenborg, an avian sleep researcher at the Max Planck Institute for Ornithology. For one, there’s no proof birds can sleep while actively flapping their wings. The ocean-going frigatebirds only slept about 45 minutes a night compared to more than a total of 12 hours a day back on land—and none of that was while flapping. What’s more, extreme sleep deprivation doesn’t seem to affect birds as drastically as it does humans. How much time these animals need to sleep is relatively flexible, he says. In fact, related research in migratory Pectoral Sandpipers found males that slept the least during the breeding period performed the best: They fathered more offspring.
For now, batteries that power gear scientists use to track bird movements and brain activity in flight are too big for most species other than sizable frigatebirds, which wore trackers on their backs and heads. Definitive answers about migratory sleep will require a technological breakthrough.
This story originally ran in the Spring 2022 issue as “Enduring Mysteries.” To receive our print magazine, become a member by making a donation today.
02
The spider that looks like bird poo—and other amazing (and gross) tricks animals deploy to survive
Animals do all sorts of disgusting things. While these gross behaviours might turn our stomachs, they're often crucial to an animal's survival.
I and my colleague Nic Gill have done the dirty work, and collected a bunch of unexpected facts about how these behaviours help animals live their best lives: making a home, finding mates and food, and surviving predators.
Our new book, titled "Poo, Spew and other Gross Things Animals Do," is aimed at kids, but much of it will be news to adults, too.
So what does it take to survive and thrive in the wild? It's not always about being the biggest and fiercest. Many animals have evolved much more entertaining—if not impolite—strategies for evolutionary success.
Grossness in love (and self-defence)
For wild animals, finding a mate is no laughing matter. But the lengths to which some animals will go to obtain one can be.
Female lobsters wee on their potential mates' face for an invitation into their lairs. Even stranger, a lobster's bladder sits below their brain—so the wee squirts from their face.
Hippopotamuses, meanwhile, have become YouTube sensations for their rather unpleasant "dung showering" behaviour. Hippos spin their stumpy tails to propel a mixture of wee and poo up to ten metres—using the technique to mark their territory.
Hippos have also been observed flinging poo directly into their love interests' face during courtship.
Living in the wild can be tough. Unless you're a top predator, something, somewhere nearby, probably wants to eat you.
Some animals are fast enough to run away from predators—or, like echidnas, protect themselves with armour.
Others have developed more revolting survival strategies. Sperm whales for example, are known to defecate into the water "for a startling length of time" . This creates a "poo-nado"—a cloud of excrement that conceals them from perceived attackers (or unlucky snorkelers!).
And some spiders have taken advantage of the fact that birds, unlike some other animals, don't like to eat their own excrement.
As its name suggests, the bird-dropping spider has evolved to protect itself from bird predators by looking like bird poo.
The spider bears a black, brown and white colour pattern and a squat shape. It sits still on leaves and other exposed locations during the day, tricking predators into assuming its a blob of poo.
But if there was a competition for most repulsive yet effective self-defence mechanisms, it would go to Eurasian roller chicks.
When frightened, these baby birds spew a foul-smelling orange liquid all over their aggressor, and themselves. This not only deters the predator, it warns the birds' parents of danger around. Vomit as as emergency beacon—who knew?
Poo detectives
Scats (poo) and reject-pellets (spew) contain a surprising wealth of information for researchers looking at hard-to-study species.
The presence of poo or spew can help researchers determine where in the landscape a species lives—especially when, like in the case of wombats' cube-shaped poo, it's helpfully engineered to not roll away.
Poo and spew can also reveal important information about an animal's diet, through identification of the bones or genetic material present. Taking this to the next step, info from poo and spew has even been used to describe whole ecosystems.
For example, scientists have used owl spew to monitor the threatened mammals present where the bird lives. And information on an animal's disease status and gut microbiome can all be extracted from poo and spew.
These methods also have the benefit of being non-invasive—meaning researchers can check an animal's health without physically handling it.
Conservation dogs are becoming an increasingly popular method of detecting these data-rich, smelly goldmines.
3 more poo particulars
Still unconvinced by the power of poo? Consider these facts:
Creating white sandy beaches: Parrot fish have some of the strongest teeth in the animal kingdom, which they use to graze on coral. Their digestive system turns it into fine white sand, meaning parrot fish poo helps create beautiful beach destinations
Threatening the outdoor dining scene: In the 1950s, scientists realised native beetles were uninterested in eating poo from introduced cows. This left the country covered in cow poo—a perfect breeding ground for disease-carrying flies.
At one stage, flies were so numerous that outside dining was forbidden to protect public health. Eventually, poo-eating dung beetles were flown in from overseas to solve the problem.
- Cooling the planet: Researchers have shown bird poo can help fight climate change. They discovered that in the Arctic, ammonia produced from tons of seabird poo helps form clouds that can partially block sunlight.
So now you know a little about how grossness makes the animal world go round. Feel free to share these tidbits with your friends—though perhaps not while they're eating.
Poo, Spew and other Gross Things Animals Do by Nic Gill and Romane Cristescu, illustrated by Rachel Tribout, is published by CSIRO Publishing.
Citation: The spider that looks like bird poo—and other amazing (and gross) tricks animals deploy to survive (2022, April 6) retrieved 13 April 2022 from https://phys.org/news/2022-04-spider-bird-pooand-amazing-gross.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
03
7 Amazing Bird-Watching Spots In Michigan
According to the U.S. Fish & Wildlife Service, bird-watching is the second-fastest-growing hobby in the nation after gardening. Michigan features a wide range of habitats for birds, and as a result, birdwatchers have spotted over 450 species in the Great Lakes State. From shorebirds along the Great Lakes coastline to birding trails, state parks, and bird sanctuaries, Michigan is a paradise for birders, with over 2 million residents enjoying bird-watching.
This article will cover seven of the best bird-watching hot spots in Michigan, where they are, and which birds to look for while you’re there. Here are some of my favorite Michigan bird-watching spots that represent a variety of birds. I listed them from north to south.
Note: My visits to Copper Harbor and Kalamazoo were partially hosted trips. The opinions offered are based on my experience.
Brockway Mountain Drive near Copper Harbor Brockway Mountain Drive (Lane Alholinna / Shutterstock.com) 1. Brockway Mountain Hawk Watch, Copper Harbor
Located in the Keweenaw Peninsula, you’ll take Michigan 26 west from Copper Harbor, and Brockway Mountain Drive is the first road on the left. This seasonal road has a steep slope, but the effort is worth it for its stunning views of the water and woods below. The official Brockway Mountain Hawk Watch takes place between March 15 and June 15. While it depends on the weather, mid-May is generally the peak timing. Birds stop in Keweenaw to prepare for their flight over Lake Superior and on to Canada. During this time, counters have documented 15 types of hawks. Falcons, owls, turkey vultures, and eagles contribute to the thousands of birds found in this area during migration.
Other birds frequently spotted include the cedar waxwing, snow bunting, cackling goose, American pipit, and the rusty blackbird.
From the end of April through mid-May, the Annual International Migratory Bird Festival occurs. During the festival is the perfect time to learn more about birding through a series of birding activities, dinners, and programs.
Pro Tip: If you’re looking for a place for lunch or dinner, the seasonal Eagle Harbor Inn is a perfect choice while in the area. Stop by Jampot, a monk-run bakery that offers the ideal snacks to take on the trail for a sweet treat.
Whitefish Point Bird Observatory Fsendek / Shutterstock.com 2. Whitefish Point Bird Observatory, Paradise
Situated in Michigan’s Upper Peninsula 11 miles north of Paradise, you’ll find the Whitefish Point Bird Observatory on the point of land that protrudes into Lake Superior. Before making the long journey across Lake Superior, thousands of birds will use Whitefish Point as a place to refuel and prepare. Hence, the region is a Globally Important Bird Area, where birdwatchers have identified about 340 species of spring and fall migratory birds in this corridor.
The Michigan Audubon runs a research project that counts waterbirds and raptors during migration. They also monitor piping plovers and band owls.
To discover more about the area’s maritime history, you’ll want to explore the Great Lakes Shipwreck Museum, where the Edmund Fitzgerald’s 200-pound bronze bell is on display.
Pro Tip: Tahquamenon Falls is a must-see while you’re in the area. Approximately 20 minutes from Whitefish Point, Tahquamenon Falls Brewery & Pub, located in Tahquamenon Falls State Park, makes the perfect place for a meal after birding or exploring the falls.
Trumpeter swans at Seney National Wildlife Refuge Trumpeter swans at Seney National Wildlife Refuge (Wildnerdpix / Shutterstock.com) 3. Seney National Wildlife Refuge, Seney
Located about 12 miles north of U.S.-2, Seney National Wildlife Refuge offers the perfect place for birders to get back to nature for a day. First, stop by the visitor’s center, where the staff can orient you to the grounds. Then, check out the observation decks that offer spotting scopes to watch for osprey nesting.
Since I have difficulty hiking, I particularly enjoy the Marshland Wildlife Drive at Seney, where I could enjoy some of the best birding from my car. With a habitat for more than 200 bird species, you’re likely to see a variety of waterfowl and raptors — trumpeter swans, common loons, bald eagles, osprey, and sandhill cranes. The Pine Ridge Nature Trail is an excellent option if you prefer walking. Go to their website for a list of the dozens of birds you might see.
Other ways to enjoy the refuge’s outdoor activities include Northern Hardwoods Hiking, cross-country ski trails, and snowshoeing, with miles and miles of unpaved roads for hiking and biking through the backcountry.
While there’s no camping in the almost 96,000 acres of the Seney National Wildlife Refuge, you can camp in the nearby Fox River State Forest Campground.
Pro Tip: For spring migratory birds, visit in May, but be sure to wear long sleeves and don some bug spray, as the area is prone to bugs during May. For fall migratory birds, September and October are the months to visit.
Rose-breasted grosbeak at Hartwick Pines State Park Rose-breasted grosbeak at Hartwick Pines State Park (Stubblefield Photography / Shutterstock.com) 4. Hartwick Pines State Park, Grayling
Located about 2 hours north of Michigan’s capital city Lansing, the area near Hartwick Pines State Park in Grayling is home to one of the world’s rarest birds, the Kirtland’s warbler. They also call them jack pine warblers because they breed almost solely in the jack pine forests in the northern part of Michigan’s lower peninsula. Unfortunately, the only way to see this conservation-dependent species is to take a guided tour of the nesting area.
The Michigan Audubon and Hartwick Pines State Park partner to provide guided tours between mid-May and early July. In nearby Roscommon, on the first Saturday in June, they also hold the Kirtland’s Warbler Festival.
The Michigan Audubon offers a variety of tours, and each has a difficulty rating listed on its events calendar. Check those listings for walking distance, terrain, and tour duration.
Pro Tip: At least once a summer, I pass through Grayling on my way up north, and I always stop by Dead Bear Brewing Company. One of my favorite sandwiches is the Aporkalyse Burger, a cheddar cheeseburger topped with in-house smoked pulled pork, bacon, ham, and barbecue sauce.
A cerulean warbler in a maple tree A cerulean warbler (Frode Jacobsen / Shutterstock.com) 5. Otis Farm Bird Sanctuary, Hastings
The Michigan Audubon owns and operates the 128-acre Otis Farm Bird Sanctuary. Located adjacent to the Barry State Game Area, it is a Globally Important Bird Area for giving cerulean warblers a breeding habitat. The Michigan Audubon offers cerulean warbler guided tours early through late May at 8 a.m. at the Otis Farm Bird Sanctuary. Note that when trying to find the tour location, GPS trackers may not be accurate. It is best to use the directions on their website to find the correct place.
Spring and summer are the best times to go bird-watching at Otis Farm Bird Sanctuary. In addition to warblers, you’ll likely find red-headed woodpeckers, osprey, sandhill cranes, and various sparrows. While you’re in the area, you can discover more nature by biking at Hammond Hill Trail.
Pro Tip: For lunch after your exploration, try San Marcos Mexican Bar & Grill.
Whitford Lake at Fort Custer Recreation Area Whitford Lake at Fort Custer Recreation Area (Dean Pennala / Shutterstock.com) 6. W.K. Kellogg Bird Sanctuary, Augusta
Located in southwest Michigan, about 15 minutes from Kalamazoo in the town of Augusta, W.K. Kellogg Bird Sanctuary is a tranquil area to sit and observe waterfowl, like Canada geese, ducks, and trumpeter swans. In addition, their birds of prey enclosure features eastern screech owls and bald eagles.
At the center of the sanctuary, you’ll find Wintergreen Lake. Although this is a year-round location, and we visited in the winter, spring through fall is the best time to visit. Even in the winter, we saw various birds feeding at the bird feeders, including cardinals.
You’ll find about 3 miles of trails, so it’s a great place to get outdoors for a walk where you’ll see lots of other wildlife besides birds. Take a picnic lunch, as there are plenty of picnic tables to enjoy an alfresco meal. A small general entry fee applies.
Also in Augusta, the Fort Custer Recreation Area provides another opportunity to get out into nature with hiking, horseback riding, and swimming. I also enjoy the Gilmore Car Museum while I’m in the area. The museum is the largest car museum in North America.
Pro Tip: Stop by Player’s Grill and give their famous burgers a try.
Sand dunes at Warren Dunes State Park Andy Wilcock / Shutterstock.com 7. Warren Dunes State Park, Sawyer
Situated about 15 miles south of St. Joseph in Sawyer, Warren Dunes State Park offers 1,952 acres, including open dunes and wooded birding habitats. With 3 miles of shoreline, you’ll find shorebirds, gulls, terns, and waterfowl along the beach. In addition to birds, you’ll have stunning views of Lake Michigan from the top of the 260-feet dunes.
Over 6 miles of hiking trails are home to raptors and songbirds. One of the best areas in the park for birding is the Organizational Youth Camping Area.
Warren Dunes State Park has two campgrounds and some rustic mini cabins if you enjoy camping. You’ll relax to the sounds of Lake Michigan’s waves in their lake-front camping. Whether you prefer modern with hot water, bathrooms, and electricity or a more rustic campsite, you can have it all in this park.
Pro Tip: Vehicle entry and parking in Michigan State Parks require a valid Recreation Passport.
To learn more about Michigan and birding, check out these articles:
