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Featured species: Common Loon
Loons are the iconic bird of Canada – enshrined on our dollar coin and found across most of the country. Some may have already arrived in your area to nest but migrants are still staging on open water, or over-flying us as they head further north. Whether you just have them for a short time in the spring and fall, or are blessed with them throughout the warmer weather, their eerie voices remain a quintessential ‘call of the wild.'
Few waterfowl have as wide a range of vocalizations, each with its own meaning:
Description: Wolf-like howl; 2 seconds
Meaning: Summons mate/offspring
Description: Laugh-like; 1 second
Meaning: Alarm; flight call
Description: Wail, plus yodel-like undulations; to 6 seconds
Meaning: Territorial by male, spring dusk to dawn
Description: Short, soft ‘hoo’
Meaning: Maintain contact in group
Loons are divers more so even than flyers, having solid bones and feet placed far to the rear that help it dive to 80 m and stay under for almost a minute. Of course, those bones also contribute to the long, running takeoffs (up to several hundred metres on a calm day) required to get airborne. Once on the wing, however, they can reach speeds of 120 kph. Common Loons will also use visual displays to communicate:
- Bill dipping, which may reduce aggression when two or more birds meet in group situations (0:45);
- males standing up and treading water, often with wings out and yodelling, is a classic territorial display (:30); and
- males extending the head and neck low on the water (often yodelling) is also territorial.
Beautiful on the water, they are ungainly on land, building minimal nests in protected spots (islands, half-submerged logs) right next to water. Where significant water level fluctuations are an issue, nesting platforms are one response. Currently, loons are engaged in courtship and mating (1:10), but eggs will not be laid until early June.
Although Common Loons are protected by law, they are showing reduced breeding success and have abandoned some of their breeding range in more populated areas, likely due to shoreline development and nest disturbance. Low-lying, nests are particularly susceptible to boat wakes. Loons are also dying from high concentrations of mercury
in their tissues, the latter from ingestion of lead fishing sinkers. If you boat or fish, give nesting areas a wide berth, and consider using non-lead alternatives for sinkers and jigs. Here is a 3-lesson unit on loons for Grades 4-7.
- Note: Almost too much is happening now to keep up with, much less write down here. I can only mention a few representative events and species. Keep your own eye out for happenings in your area, and let the rest of us know about them.
- American Toads complete the amphibian chorus, their long trills (embedded in previous link) coming from possibly any patch of standing water or backyard pond, day or night. Lasting up to 30 seconds, each competing male will call at a slightly different pitch. They will also try to mate with almost anything that moves, finally clasping the much larger female from the back. Mating can be easily observed soon after calling starts. Toad eggs are in ribbons or strings, rather than the clumps that frogs produce.
- Many of you will soon be treated to the first hatch of black flies, confirming that water quality is pretty much up to snuff. Limited to fast-running streams, black fly production can be over 30,000 individuals/metre2/season. The first wave comes from larvae that have grown over the winter, while later hatches come from larvae that overwintered as eggs. If you look carefully, you can actually see adults pop out on the surface and buzz around a bit before flying off to a bit of vegetation to rest and harden. While most black fly species produce only one adult generation/year, females may produce eggs 2-3 times per season, and may emerge ready to lay eggs that don’t require a blood meal. Unfortunately, though, most do, and while not all black flies bite humans, enough do to make things miserable for a while. Both sexes also feed on nectar, and contribute to plant pollination (eat a blueberry, thank a black fly), as well as to meals for flying insects like damsel- and dragonflies, bats and insect-eating birds.
- There is now a veritable avalanche of birds arriving from Central and South America, including a number of beautiful warblers that are mostly passing through: Yellow, Palm, Nashville, Blackburnian, Cape May and Cerulean, among others. As in the fall, if you go out on calm nights you may be able to hear contact calls from the massive flocks heading north at this time.
- Other avian arrivals include: Black Terns, Eastern Kingbirds, House Wrens, Ovenbirds, White-crowned Sparrows and Baltimore Orioles. Migrants respond to weather, pinned in place by north winds and advancing far on southerly ones. Rainy mornings are good times to check for migrants just hanging around, even in city backyards or schoolyards with a bit of shrubby edge habitat. Check also woodlots, hedgerows, roadsides and wetland margins.
- Migrating northward at the rate of about 40 km/day, Ruby-throated Hummingbirds will be arriving soon if not here already, so keep your eyes peeled!
- Consider joining Bird Studies Canada’s Schoolyard Bird Blitz, an annual May bird count by students across Canada who will explore their schoolyard, count local birds and share their findings. If your school is closed and you have bird nests in your yard or neighbourhood park, try Project Nestwatch and monitor nesting activity (please check your public health guidelines before going off your property). Contribute to citizen science!
- Midland Painted Turtles will again be out basking on logs and rocks in southern Ontario and Quebec wetlands, at times raising their body temperature 8-10 degrees above the surrounding air. This temperature is needed to hunt, digest and develop eggs.
- Spring butterflies may be out early this month, again dependent on temperatures. They need an extended period of warm weather for their hibernating chrysalids to change into adults. Look for Olympia Marble , Chryxus Arctic, Cabbage White and Hoary Elfin. Check those shrubby margins, fresh Sapsucker holes and especially lilac blossoms. Maple trees can attract Comma butterflies with their sap, and a few Red Admirals may pop up.
- By mid to late April, the Monarch migration from Mexico was still struggling to breach the Mason-Dixon Line, and the next generation has begun popping up. Milkweed growth appears to be preceding the butterflies, sprouting as far north as Oakville and Toronto, Ontario.
- White-tailed Deer does are banishing their male offspring from the immediate area prior to giving birth, in order to minimize interbreeding. So watch the roads for roaming deer.
- Common Horsetails, small, primitive remnants of once-massive Carboniferous forest tree-like plants, can be found in damp areas along roadsides. Sometimes spore cases can be seen at the tips of the jointed stems. Horsetails require water for sperm to be able to access eggs. Smaller stems will eventually ‘leaf out’ of the joints, producing a brushy appearance. Bits of silica sand reinforce the stems, and their granular texture reflects the name, ‘scouring rush.’
- Whites and yellows are the main colour themes for many early bloomers. Look out for Red and White Trilliums, Spring Beauty, Yellow Trout Lily and Early Meadow Rue. Woodland herbs must pack a lot of growing into the short time before the canopy closes and light is reduced by up to 99%. Look for insects around these plants.
- Trees that normally leaf out here at this time include Pin and Choke Cherry, Manitoba and Norway Maple, Trembling Aspen, Serviceberry (flowers before leaves ) and the willows. Leaf out can proceed very fast, so pay attention! Sketching leaves from one day to the next can show marked changes as they unfurl. Some leaves lie fully-formed within the buds and just have to be ‘inflated’.
- May 5 is the mid-point of spring and in Southern regions the last frost generally occurs by mid-month or a bit later. It may be sooner or later where you are – find out, and compare that to the actual last day of frost this year.
- If you missed the Lyrid meteor shower, you might try the Eta Aquarid shower to the southeast an hour or two before dawn on May 4-6, and may be best to look on the 4th after moonset. It will be best in the Southern Hemisphere, but you might catch the odd meteor if you’re up anyway.
- Venus slowly falls back toward the horizon this month, and once it’s gone, it won’t be seen in the evening sky until next spring. The last full supermoon of the year will occur on the 7th.