Where’d My Hummingbirds Go?

Jan Thornhill

I’ve spent a lot of time this summer sitting outside working on my laptop directly below our hummingbird feeder. At least two families have been regularly zipping in and out to supplement their usual diet of insects and nectar gleaned from flowers. Hummingbirds can get along just fine without sugar water, but it’s clear they like it: whenever the feeder runs dry, they let us know by buzzing so close to our faces we can feel the wind created by their ridiculously fast-beating wings.

This tiny spot on my laptop is a hummingbird dropping.

Several weeks ago, though, there were suddenly fewer feeder visits. It was obvious that some of our hummingbirds had disappeared. I might have thought something tragic had happened if I hadn’t just spent a year researching and writing a picture book about migration – Is This Panama? – so I knew that my “missing” hummingbirds were likely adult males who had simply flown the coop. In Ontario, these males normally begin their “fall” migration as early as the last week of July, which allows for a leisurely journey to Central America, where they spend the winter. Adult females wait a while longer before taking off, followed much later by the juveniles.   

Juvenile hummingbirds, like this male ruby-throated, migrate south later than adults.

Many of our other smaller summer birds, such as warblers, also travel south over an extended period of time, so their fall migration can seem much less dramatic, and less obvious, than the spring migration when everyone’s racing north to stake claim on the best breeding and feeding grounds.

Looking for Songbirds in the Fall

Where: 

Goldfinches love thistle seeds (Will Sweet)

In late summer and early fall, grasslands and wildflower meadows attract both seed- and insect-eaters. Though mature forests are a great place to look, heavy leaf cover can make autumn bird-spotting more difficult, so seek out clearings and forest edges where warm morning sun can activate insects. Waterside areas can be fruitful too. And don’t forget your neighbourhood park or your own backyard!

When: 

Though hummingbirds migrate during the day, many other species migrate at night. These nocturnal migrants have evolved to navigate using the stars during the hours when strong winds have died down and cooler temperatures reduce the risk of overheating. On a clear night, with a slight north wind, these birds might fly for ten hours straight, so there can be good viewing opportunities the following day as the birds stop to rest and feed. If you’re a night owl, aim binoculars or a viewing scope at a full moon and see if you can catch a group of migrants silhouetted as they fly past!

Warblers: 

More than 30 species of warbler nest in Canada and, though their colours are muted in the fall, these tiny birds are still incomparable in their beauty. The problem with fall warblers is that they don’t advertise their whereabouts with song the way they do in spring. They do, however, produce delicate chipping notes that help to pinpoint their location. Another way to find them is to listen for vocal chickadees, since chickadees regularly join up with migrating warblers into loose foraging flocks.

Black-and-white warblers creep up tree trunks like woodpeckers. (Mike & Chris)

Help Them Out!

• Put seed in your birdfeeders and replenish hummingbird feeders. Even after your local summer birds have left, migrants from further north may pass through and stop for a snack.  
• Grow native plants in your garden and don’t deadhead flowers. Sunflowers hanging with ripe seed are amazing natural birdfeeders.
• Ground foragers, such as sparrows and doves, are attracted to brush piles and leaf litter, so wait until late fall to clean up your garden.
• Pesticides, herbicides, and fungicides can be lethal for birds, so avoid their use.
• Keep your cats indoors or watch over them while outdoors. Though cats make wonderful pets, they kill more than a billion wild birds every year in North America.

Children’s Resources About Bird Migration:

• Is This Panama?: A Migration Story – Jan Thornhill (Author), Soyeon Kim (Illustrator)
• Moonbird: A Year on the Wind with the Great Survivor B95 – Phillip Hoose
• On the Wing: American Birds in Migration – Carol Lerner 
• The Long, Long Journey – Sandra Markle 
• How Do Birds Find Their Way? –  Roma Gans (Author), Paul Mirocha (Illustrator)
• The Peregrine's Journey: A Story of Migration – Madeleine Dunphy (Author), Kristin Kest (Illustrator)
• Winged Migration (Academy Award winning DVD)
• you can also follow the hummingbird migration south at:  http://www.learner.org/jnorth/humm/fall2013/update082313.html 

Help Save the Monarch Butterfly!

by Jan Thornhill

What’s not to like about monarchs? Their caterpillars are gorgeously striped. Their chrysalises are an otherworldly green bejeweled with glimmering gold. The adults weigh only half as much as a paperclip, yet can migrate thousands of kilometres—and if you’re lucky enough to be in the right place at the right time you can see congregations of thousands. Monarchs can also make blue jays throw up—a delightful tidbit I learned while researching my new book about migration, Is This Panama? (beautifully illustrated by Soyeon Kim!). Sadly, just as the book went to press, bad news arrived: the over-wintering monarch population in Mexico was the lowest ever recorded.

Roosting monarchs (Agunther)

Hundreds of millions of monarchs migrate each fall to warmer areas. Adults that originate in southern Canada can fly more than 4,000 kilometres (2,500 miles) to reach their hibernation grounds in Mexico. It’s a treacherous journey for a delicate butterfly and many die on the way, but every year millions arrive in a mountain forest near Mexico City. Because it would be too difficult to actually count such large numbers, scientists have been measuring the area of forest each year that the butterflies occupy. In 2011 monarchs covered the trees in 2.89 hectares of forest. This past winter they occupied only 1.19 hectares (5 sq. miles)—a drop of 59%!

Though adult monarchs sip nectar from a variety of flowers, their caterpillars are specialist herbivores, which means they depend on a single type of plant for food. In the monarch’s case, these plants all belong to the milkweed family.

Between hatching and forming a chrysalis, monarch caterpillars increase 3,000 times in size. These two caterpillars are in their second and third stages of growth, called instars. (Jan Thornhill)

Milkweeds have evolved elaborate defenses to prevent themselves from being eaten, including uncomfortably hairy leaves, sticky white latex that bleeds from injured tissues, and toxins called cardenolides. Because of the cardenolides, most insects, as well as vertebrates, avoid eating milkweed, but the monarch has evolved to not only tolerate the toxins, it also uses those very poisons to its own advantage by storing them in its own body, which makes even an adult butterfly just as toxic as the plant. The first time a bird, such as a blue jay, eats a monarch, it will vomit a short time later. Though this is of no benefit to the monarch that was eaten, the bird will remember its bad experience and will avoid eating black-and-orange butterflies from then on.

Meanwhile, milkweed plants are continuing to evolve in response to being eaten by caterpillars. Recent genetic research is showing that there is an evolutionary trend in milkweeds towards healing themselves faster than they can be eaten, instead of producing more toxins that might eventually deter caterpillars. 

Monarch caterpillar on milkweed flowers (Jan Thornhill)

Though milkweeds can get along perfectly well without monarchs, monarchs cannot survive without milkweeds. Unfortunately, milkweeds of all varieties are disappearing. Their grassland habitats have been steadily eroding for more than a century due to human development, and recent severe droughts in Texas and the American Southwest have also taken their toll. But another much greater threat has arrived: farmers across North America are now growing corn and soybeans that are genetically engineered to be herbicide resistant. When these “Roundup Ready” crops, developed by a company called Monsanto, are sprayed with glyphosate-based herbicide, almost any plant—other than the corn and soybeans—is killed. The plants that once grew alongside these crops include milkweed, which, until now, had always been plentiful, as well as a multitude of wildflowers that provide nectar for adult butterflies while they’re migrating. One study has shown that between 1999 and 2009 there has been a 90% loss of common milkweeds in the fields treated with these herbicides.* Soon there may be no milkweed in these croplands at all. And no monarchs.

So What Can We Do To Help?

Grow milkweed in your backyard or in your schoolyard:

http://monarchwatch.org/bring-back-the-monarchs/resources/plant-seed-suppliers

http://www.livemonarch.com/free-milkweed-seeds.htm

Grow a “butterfly garden” with plants that provide food for caterpillars and/or nectar for butterflies:

http://www2.ville.montreal.qc.ca/jardin/en/info_verte/papillons/papillons.htm

 Learn more about monarchs and share what you learn: http://www.monarchwatch.org

Help monarch researchers: http://www.monarchwatch.org/class/studproj/index.htm

 

Lobby your political representatives to have products made with genetically modified (GM) crops labeled.

*Pleasants, J.M and Oberhauser, K.S.. 2012. Milkweed loss in agricultural fields due to herbicide use: Effect on the Monarch Butterfly population. Insect Conservation and Diversity (March 12, doi: 10.1111/j.1752-4598.2012.00196x)