the real “snow-birds”

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.

Ruby-crowned Kinglets are some of the smallest birds (besides hummingbirds) that pass through this area in the spring and fall. They weigh just half as much as a Chickadee (0.2 ounces or about 6 grams), — tiny bundles of energy that never stop moving for an instant as they continuously search for food.
There are fewer insect blooms in the fall for these birds to fatten up on. Look at the size of the miniscule prey item this bird is after on the underside of the the leaf — it would have to eat hundreds of them to get enough energy to sustain it for one day, let alone try to put on enough fat to provide energy for migration.
Magnolia Warblers, and most other warbler species, are only slightly bigger than the kinglets, weighing about 7-11 grams (0.2-0.4 ounces) depending on whether they have just fattened up to leave an area, or have just arrived desperate to find their next meal.
Eastern Wood-Pewees are tiny little flycatchers (weighing just slightly more than a fat warbler at 0.5 ouces or about 14 grams) that perch on bare branches and fly out to attack insects flying by.
Red-eyed Vireos are about 50% bigger than a Chickadee, weighing in at about 0.6 ounces or 17 grams.

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.

Philadelphia Vireo with a mouthful of dogwood berry. Fruit-eating birds are really good at separating the nutritious part of the berry from the indigestible parts, and pass the waste through their digestive tract quickly to make room for more berries. (Note: don’t stand under a fruit-eating bird while it’s moving food through its gut!)

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!

Figure from SciNews, March 2019. A fascinating summary of a study by DeLuca et al. published in the journal Ecology in 2019.
Of course, the bird that defies predictions of how far it can fly on its fat supply is the Ruby-throated Hummingbird — a 3-gram (0.1 ounce) bird that routinely flies 500 miles across the open water of the Gulf of Mexico for 18-22 hours to the coast of South America, rather than follow the longer land route through Central America. Now that’s a physiological marvel!

the chase is on!

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.

Last year at this time we visited Hawk Ridge nature reserve on Skyline Drive west of Duluth. On any given day, tens of thousands of hawks pass over this ridge gaining altitude to soar effortlessly south.

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.

Merlins exhibit the typical falcon profile, but they have dark brown stripes down the breast, and a heavily barred tail.
I’ve highlighted the Merlin as it takes off. It was surrounded by 4 Blue Jays squawking loudly and a Pileated Woodpecker just minding its own business — but all of them are risking an attack by this fast-moving falcon if they get too close.
The Merlin made a dive at one of the Blue Jays and just narrowly missed it as it kind of tumbled down. Merlins are agile and FAST flyers with their swept-back wings and flared tail.

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.

This is a juvenile (hatched this summer) Cooper’s Hawk, and it’s hungry! I watched the bird make half a dozen attempts to catch something as it flew back and forth from tree to tree.
A female or juvenile Pileated Woodpecker, very far away, but completely oblivious to the Cooper’s Hawk eyeing it from about 100 yards away.

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:

A quick take-off…
Followed by a few wing flaps, as the Cooper’s Hawk quickly makes its way from one set of trees to another.
The hawk returns and is now flying directly at the tree where the woodpecker is working.
You might think the Woodpecker would try to fly away at this point — but perhaps he is actually more vulnerable flying. Woodpeckers aren’t the fastest flyers as they flap, flap, glide over the landscape.
This is looking a little more dangerous for the woodpecker! Hawk in full attack mode.
The hawk puts on the brakes, flaring its tail and dropping its wings to slow down. It might have tried to knock the woodpecker off its perch, but the woodpecker seems to have turned to face its attacker. And Pileated Woodpeckers do have a pretty fearsome weapon to defend themselves from this kind of frontal assault — a very large and sharply pointed bill.

I think the woodpecker won this confrontation, and eventually the Cooper’s Hawk flew off to pick on some, other less formidable prey.

Mrs. Pileated, foraging on the tree right outside my porch windows, showing off her sturdy beak that can pound holes in hardwood trees with ease.

the “good morning” hummingbird

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…

Salvia flowers are the right color, the right depth for the hummingbird’s bill and tongue, and the right fit for its head to pick up pollen from the flower’s protruding anthers.
Peek-a-boo, it looks like the hummer is keeping an eye on me while I’m keeping an eye on it.
I never get tired of watching their acrobatic flights between flowers as they probe each one for the tiny bit of nectar at the bottom of each floral tube.

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.

it’s feeling fallish

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 beach along the Minnesota side of the St. Croix river is deserted…just the way I like it. There are a few warblers around, geese are flocking up in preparation for migration, and the last of the summer wildflowers are holding onto their blooms, just a little longer.
A somewhat bedraggled Great Spangled Fritillary was foraging on the Sneezeweed flowers — just about the only wildflowers left along this shoreline of the river. This is one of the largest, and longest lived butterflies here in MN. It mates in June but doesn’t lay eggs until August and September, somewhere near a patch of violets, on which its larvae will feed in the spring.
Cedar Waxwings were acting like flycatchers as they perched and then sallied out to catch whatever insects were flying by their perch.
And the ever-present and numerous Canada Geese are now gathering in large flocks to prepare for migration. Here they come downriver right at us…
They fly so closely together you would think their wings would get in the way of each other. In fact, so close that two birds on the right side of the photo look like one bird with four wings!
Nothing symbolizes fall in Minnesota like these flights of Canada Geese.
Fall may be my favorite season, even though it leads into my most dreaded season of bitter winter. But I love the fall weather and color as the landscape begins to glow.

the termite feast

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.

Winged phase termites emerging for their mating flight might get gobbled up by insectivores perched nearby. They emerge in swarms, but are rather clumsy, slow fliers, so they are easy to pick up.
A Chestnut-backed Chickadee was watching from a tree while Bushtits darted out from the bushes below it.
One of many Common Bushtits foraging on the termites. They flew right up to us, close enough to touch as they grabbed termites flying around us. The white iris means this is a female.
Adult male (or juvenile) on the left and female bushtit posed together briefly before darting out to catch termites flying by. Bushtits are highly gregarious even when foraging, and will line up on a branch sitting right next to each other when they are roosting. They only weigh about 5 grams, less than half of a chickadee’s weight, so their little bodies cool off quickly. Even on a warm day, they puff up their feathers so they look like little puff-balls.
A Hermit Thrush peeked out from the underbrush but wasn’t brave enough to approach the source of the termite emergence near where we were standing.

But another bird was completely unperturbed by our presence, and amazingly, hopped right in front of us to grab termites off the ground.

If it had not been for the termite explosion in the Bay Area the past couple of weeks, I’m not sure we would ever have seen this handsome Townsend’s Warbler, which normally hangs out in the tops of coniferous trees in coastal forests. I don’t think ground feeding is something it does often.
But when you’re hungry and on migration from the northwestern U.S. and western Canada to southern coastal and central Mexico montane forests, you capitalize on easy prey when it is available. This little male moved around on the ground right in front of us, grabbing bites of termites as they emerged from a hole in the ground.
Completely out of its usual habitat of cool coniferous forests, Townsend’s Warbler brief appearance in the scrub vegetation in an urban creek area was a real treat for us.

Jays of the forest

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.

Like its eastern cousin the Blue Jay, Steller’s Jays have a crest, and like Blue Jays and Scrub Jays, they are intensely curious, especially of photographers creeping up on them, This bird played hide and seek with me, dodging behind tree stumps and hiding in thick brush as I tried to get a better angle on it.

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.

The hike along Steven’s Creek park in Cupertino was cool and rather dark with all the evergreen vegetation over the trail. Finding birds in the dense vegetation is challenging, and there isn’t much light to work with.
Steller’s Jays prefer the mixed deciduous and coniferous forests of the coast range of California. In the Sierra Nevada and Rocky Mountains, they are usually found in coniferous forest at low to mid altitudes.
“can you see me now?” Darn bird, hiding in the sticks.
I had never noticed before that Steller’s Jays have turquoise eyebrows running vertically up their crest. They can also flare their crest forward or flatten it down, depending on their mood.
Their curiosity makes them adept at finding new food sources, so Steller’s Jays are quick to find bird feeders, or new eggs or nestlings in another bird’s nest, or a source of acorns they can cache for later. And they seem to have excellent memories for where they have hidden their food treasures.

Another beautiful fall day

We should be having rain in California now, but I am grateful for a succession of warm, sunny days and walks along one of the several creeks that run through the city of San Jose.

The trail that runs along the Los Alamitos creek in the Almaden valley is lined with sycamores that glow yellow-orange in the late afternoon light.
Fall color is at its peak in the city, with boulevard trees showing various hues of red, orange, and yellow and riparian vegetation dominated by the yellow-orange hues of the giant sycamores that line the banks of the creek.
The Los Alamitos creek trail runs about 5 miles along this creek, with an asphalt walking/biking path on both sides, and numerous foot/horse trails nearer the creek.

How fortunate local residents are to have this scenic natural area to explore as often as they wish, especially during this delightful fall weather.

The white-tailed mouse hunter

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?

If the wind is just right, these long-winged raptors barely have to flap to stay in position. They are striking birds, with their white head and body, gray-black shoulder patches, and orange eyes.
Typically, the kites hovered or soared over a spot until they spotted something moving below and then dove down on it, feet extended and wings up.
We didn’t see a successful capture on this particular day, but we did see several attempts, with bird pulling up at the last moment to continue its search.

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.

White-tailed Kites maintain a breeding territory and defend it from other kites or potential predators. They tend to roost or nest in the same spot, and I spotted this pair in the same tree on two successive days, so maybe this was a favorite hang-out for them in their territory.
The kites were clearly upset by a pair of Red-tailed Hawks circling over a grassy hillside nearby and flew over to the hawks to dive-bomb them a couple of times.
My new favorite bird, — the White-tailed Kite.

New favorites

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!

Hillsides of oak savanna and chaparral surround the long arm of the reservoir. The shallow water at one end is a perfect place to find ducks and shorebirds.
Several species of ducks, herons, egrets, Kildeer, and even a couple of Snipe were working the shoreline of the reservoir as we walked past.
A trail winds in and out of contours in the hillside along the reservoir.
A forest of valley oak lead downhill to the water.
At points along the trail, a hiker may be inundated with the wonderful aroma of California Bay trees.

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.

My new favorite bird, the White-tailed Kite!

When I see a new bird, I have to take a couple hundred photos of it, just to make sure I get one that is decent. This particular kite was hovering over a field looking for mice or frogs or something, and stayed in one spot, hovering and riding the wind, making it very easy to get lots of good photos.

Back to fall weather

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.

The trail runs about 5 miles along the burbling and clearwater Los Alamitos creek in southwestern San Jose, CA.
Flitting about in the underbrush were two male Ruby-crowned Kinglets that were more consumed with fighting with each other than with a photographer standing nearby. It’s almost impossible to get this close to these birds in Minnesota.
Gnarled tree roots of the big sycamore trees that line the creek bank make good perches for flycatching birds.
Sure enough, a little Black Phoebe was hunting there, flying out from a perch to grab insects flying by and then settling down on a tree root again.
A beautiful sycamore parkland!