The Fall bird migration is in full swing here in Minnesota, and large numbers of some of the smallest migrants have come and gone already on their long journey from their breeding grounds in Canada and Alaska to their over-wintering areas in Central and South America. These are the species that are obligate insect- or fruit-eaters that simply cannot find enough to eat during the cold winters of northern North America to survive here. So they leave well before the snow flies.
Kinglets, Warblers, Vireos and Flycatchers (like the Eastern Wood-Pewee) eat an insect-rich diet most of the year, but because there are fewer insects around in fall (compared to spring), they often utilize berries, suet, and even seeds as energy sources to store fat for the next leg of their migration. Because insects and fruit are mostly water (70-80%), these tiny birds need to eat about 1.5 times their body weight each day in order to put on just 0.5 grams of fat per day. But that’s not enough to fuel a 500 mile flight to the next stop on migration, so it takes 3-4 days of constant eating and putting on fat to get enough fuel on board.
Blackpoll Warblers are the kings of metabolic physiology when it comes to putting on fat for long-distance migration. These half-ounce (14 gram) birds double their body weight before flying non-stop for 4-5 days on one leg of their journey across part of North America and the Atlantic Ocean to reach their wintering grounds in the Caribbean Islands and northern South America. That means their little bodies are 50% fat when they take off — literally, butter-balls of bird!
We tend to see a lot of songbirds, especially warblers, sparrows, flycatchers, thrushes, vireos, etc., migrating south at this time of year. But September is also prime time to see a lot of raptors as they fly down the ridgeline above Duluth and follow the rivers past the Twin Cities.
I just happened to be at Sucker Lake in Shoreview one morning when some of the local, or perhaps it was a few of the migrating raptors, tried to cash in on the numbers of jays and robins that had just arrived.
First up was a Merlin (a little falcon smaller than a peregrine but which quite likes to eat small birds). I found him far away in a tree being harassed by Blue Jays. Then he turned on them and tried to catch them, chasing them off their perches. But this excitement was all taking place too far away to get any good photos.
Next up was a smaller raptor, a Kestrel (sparrow hawk), which would have preferred to dine on smaller prey like goldfinches or small sparrows, rather than the Blue Jays that were dive-bombing it. All I got was a look through my binoculars before the Kestrel flew off and took refuge in the pines to hide from the jays.
And then a large Cooper’s Hawk flew onto a low perch and took a look at the jays but ignored their squawks, focusing on something much bigger — the Pileated Woodpecker, still minding its own business.
The Cooper’s Hawk made no attempts to nab the Blue Jays encircling it wherever it perched, and instead made several dives at the woodpecker, trying to pluck it right off the trunk of the tree. The action looked something like this:
I think the woodpecker won this confrontation, and eventually the Cooper’s Hawk flew off to pick on some, other less formidable prey.
What could be more pleasant than to sit outside on a coolish, bright sunny morning with a cup of coffee and a camera watching Ruby-throated Hummingbirds forage on Salvia flowers? The light was harsh and full of high contrast until the birds visited just the right flowers…
Soon these tiny bundles of energy will undertake a giant-sized migration south to the Gulf coast. There they will again stock up on sugar-rich nectar to convert to fat stores that supply the energy for them to cross the Gulf of Mexico (the smallest birds to do so), without stopping, to get to their overwintering sites in Central America.
Because of their high requirement for sugar during their migration, they become frequent visitors to backyard nectar feeders at this time of year. To keep these little dynamos healthy on migration, remember to change the sugar solution in your feeders every 3-4 days, so it doesn’t grow mold or bacteria.
We spent a beautiful morning walking along the St. Croix river at Afton State Park recently, and I noticed that it seems more like fall weather now, and a lot less like summer. What a difference a couple of weeks makes in the climate here.
The winged phase of termites were swarming last week in several places we hiked. And the local insectivorous birds were cashing in on some easy meals. One particular termite feast featured more than a dozen Little Bushtits, Chestnut-backed Chickadees, a Hermit Thrush, California Towhees, and a rare Townsend’s Warbler, all flitting about catching termites in the air or just emerging from a ground nest.
But another bird was completely unperturbed by our presence, and amazingly, hopped right in front of us to grab termites off the ground.
Hiking into cool evergreen forests in the outer coast range near San Jose CA, you immediately meet up with the “jays of the forest”, the Steller’s Jay. We hear them before we see them, and they really are stellar to look at with their vivid black and deep blue plumage.
Steller’s Jays are found only in the western North and Central America, typically in montane forests, like the coast range. In the U.S., they are found in coastal montane areas from Alaska through Canada to California and in the Rocky Mountains, where they barely overlap with the range of their closest cousin, the Blue Jay.
It’s rare (for me) to get long looks at raptors, but a pair of White-tailed Kites hunting in a grassy marsh at San Leandro reservoir were very cooperative photography subjects as they “kited” over the marsh looking for mice.
“Kiting” is a good description of what these birds do as they hover/soar 60-80 feet over an area with wings outstretched and catching just the right breeze to enable them to stay in one spot for long periods. Could there be a better subject for flight photography?
White-tailed Kites are mouse specialists, although they might also prey on birds, lizards, or even large insects. They are more common in South America than North America, and their numbers dwindled to near extinction in the1940s due to hunting and egg collection. Even now they are only found in grassy or marshy fields along the coast and some inland Central Valley locations in California and a few areas in Texas and Mexico.
One (positive) thing about restricted travel in the Age of Covid is finding new places to hike/bird watch within a few miles of places you have visited many times before. And so it happened that a new friend took us on a drive to the San Leandro reservoir part of the East Bay watershed, just 20 minutes from my daughter’s house. And now I have a new favorite hunting ground for bird photography!
The landscapes definitely held my interest, but that’s not why we were here either. It was for the birds, of course, and they didn’t disappoint.
Here’s a teaser, and I’ll post more on the bird life of Valle Vista Staging Area next time.
I love being able to go back in time — back in seasons of the year, anyway. Here in California, fall color is just starting, and we have the warm, sunny days and cool nights I associate with fall weather. So a pleasant walk along the Los Alamitos creek in San Jose is the perfect way to spend an afternoon.