the competition

They’re back, and they’re busily staking out their territories.  The Red-winged Blackbirds that is.

Red-winged Blackbird

Timing is everything when males want to control the best space and resources to attract females when they arrive, so it’s best to be the first to arrive in coveted areas.

I had heard that blackbirds had been spotted along the southern border of the Twin Cities two days ago, so I went looking for them in our nearby local marshes, and didn’t find or hear a single bird.

But a very small pond lined with cattails bordering the parking lot of the local YMCA had three male blackbirds patrolling the space and actively announcing their presence.

One bird was hiding behind branches of a tree along the busy road.

Red-winged Blackbird

And he wouldn’t move! So this was the best shot I could get. Fortunately the brick walls of the YMCA were out of focus.

Another bird called from down in the cattails, but hopped up on them momentarily for a photo.

Red-winged Blackbird

Not much aggressive action between these two birds on this cold day.

The third bird called from his perch high up on a light pole, and I didn’t bother photographing him.

I wonder which of them will win the competition for this site.  It seems to me they could do so much better for breeding sites at some of the local ponds in parks nearby…but then I don’t know what blackbirds like.

Riding down the Mississippi on a chunk of ice

And the melting continues during a weekend heat wave of 50 F.  Ring-billed Gulls hitched a ride on an ice chunk as it floated down the river toward Coon Rapids dam.

Ring-billed Gulls on the Mississippi River, Minneapolis

Just “ridin’ down the river”…

Their ride had to end, though, as their ice berg approached the dam spillway.

Ring-billed Gulls on the Mississippi River, Minneapolis

Ring-billed Gulls on the Mississippi River, Minneapolis

 

the flower picker

I remember sitting in the dark before dawn near some feeders in southeastern Arizona two years ago, just to catch a glimpse of a rare visitor to the area, the Streak-backed Oriole.  After 3 hours we did catch just a brief glimpse of “the bird” (there was only one).  Now two years later, I find they are common in this part of Mexico, and seem to like to enrich their fruit diet with a few flowers (perhaps containing nectar) plucked from various vegetation.

Streak-backed Oriole, Jalisco, Mexico

This bird was exploring the purple Jacaranda flowers, pulling them off the tree at random. Note the streaks along its back behind its head. Well-named bird!

Streak-backed Oriole, Jalisco, Mexico

Another oriole attacked the much larger flower of a banana plant. Perhaps it was attracted to the large red sheath at the base of the banana bunches.

Streak-backed Oriole, Jalisco, Mexico

The bird pecked at several places on the flower, but didn’t seem to find much.

Streak-backed Oriole, Jalisco, Mexico

And off he went…with some part of the plant grasped in his toes.

Like most Orioles, males of the Streak-backed variety are the most colorful, with females being considerably duller and less orange.  However, the species ranges from northern Mexico (occasionally venturing into southern Arizona) where the two sexes are completely different in color, through most of Central America, where the two sexes become more and more similar in coloration going south.

Why would there be such a difference between coloration of females from the northern vs southern extent of their range?

Apparently, Streak-backed Orioles maintain permanent territories year-round in the southern part of their range, where the bright coloration of the females helps territory defense.  In more northerly areas, the orioles maintain only a breeding territory, and may undergo short migrations away during the non-breeding season!

Stark! Cold! Lifeless (almost).

That was the North Shore of Lake Superior this weekend.  So much wind they closed the lifts at Lutsen mountain, and the outer doors of our motel blew right off their track.

Lake Superior, Tofte, MN

There are some interesting ice formations on the frozen part of the lake.

Wind and cold temperatures make for a stark landscape.  It’s more attractive with some people in it — cold hikers!

Lake Superior, Tofte, MN

Lake Superior, Tofte, MN

Lots of frozen waterfalls along the cliff walls of the lake.

Lake Superior, Tofte, MN

Glittering shards of ice litter the shoreline of the lake.

American crow

Crows and ravens always seem to be out hunting for food regardless of weather extremes.

crows feeding on roadkill

Most often the animals you might see are feasting on roadkilled deer.  Larger predators like wolves and coyotes arrive first, then eagles, ravens, and crows. We saw several of these feeding sites along the north shore highway.  Image from a Storyblocks Video. https://www.videoblocks.com/video/common-raven-and-some-carrion-crows-feeding-on-carcasses-ystozgp 

Just being out in this environment for a couple of hours at a time makes me marvel at the abilities of animals to survive in it.

How far can a gray squirrel jump?

If you google that question, you’ll find that gray squirrels can jump at least 4 feet straight up in the air, and at least 9 feet horizontally.  I’ve had a peanut feeder hanging in the buckeye tree about 7 feet from the trunk of the tree all winter, and just today a gray squirrel finally figured out how to get to the feeder. (Shot through the window looking into the afternoon sun with a terrible reflection.)

Gray squirrel jumping to a peanut feeder

This is a composite of two attempts wth the same flight path.  My camera could only capture two images per jump.  Note how this trajectory gets the squirrel to the feeder instead of colliding with the protective dome.  Click on the image to enlarge it to full screen.

Gray squirrel jumping to a peanut feeder

But this is where this particular leap took the squirrel before I scared it off.

The momentum of the landing creates a violent swing in the feeder, which can dislodge the squirrel that might be just hanging on with its toes.

Gray squirrel jumping to a peanut feeder

This might be categorized hanging on by your (toe)nails.

After several failed attempts involving collisions with the plastic dome over the feeder,

Gray squirrel jumping to a peanut feeder

Misjudged the landing on this attempt…

the squirrel successfully launched itself from just the right height on the tree trunk, with just the right trajectory arc, to land most of its body on the side of the feeder.

Athletic and smart, that’s the gray squirrel key to success.

Double (and triple) exposure

Setting my camera up at the window opposite the bird feeder and shooting at its fastest rate (10 frames per second) allowed me to capture birds in motion flying to and from the feeder.  The House Finches were leisurely about their arrivals and departures, so combining images using SnapSeed photo development software nicely illustrated the flight mechanics involved in a landing in one male House Finch.

Male House Finch landing on a feeder

Same bird, multiple exposures overlain on one image…3 exposures = approx. 0.3 seconds for this particular landing. Note brakes (wings outstretched) applied at the very end of landing.

White-breasted Nuthatches are not only bigger birds (thus taking up more space in my camera’s limited field of view), but came in much faster and departed much more quickly than the finches.

White-breasted Nuthatch landing on a feeder

Not a particularly good landing. It looks like the bird landed a little short of upright, but then they seem to prefer being upside down most of the time anyway. Wings flared much earlier than the finches did to slow their entry speed.

White-breasted Nuthatch leaving a feeder

Got the peanut, and then poof! the Nuthatch is out of the frame in less than 0.2 seconds.

But those little Chickadees are really tough to capture.  They flew in quickly, grabbed a seed or a peanut and departed just as quickly.  I rarely got more than one image of the same bird on approach to the feeder, which meant they were entering the camera’s field of view in less than 0.1 second.

Black-capped Chickadee arriving at a feeder

The Chickadee is using its wings to slow its approach much earlier than the House Finch did, a good indication of the speed with which they move toward the feeder.

Black-capped Chickadee leaving a feeder

And off the Chickadee goes with its treasure…quickly

I guess if you’re little and vulnerable, you need to be quick. And Chickadees definitely are that, quicker than my eye can follow.

Snowy portrait

A great surplus of the fluffy white stuff has been accumulating in the backyard this past week, and there are predictions of more to come.  Squirrels have been busy excavating in the snow looking for fallen seed.  Every now and then, they seem to take a break and just hang out on a branch.

Red squirrel in snowfall

Red squirrels are usually dashing around the backyard, scurrying up branches, hopping from limb to limb. This one stopped for a short rest.

Red squirrel in snowfall

The more typical view of red squirrels, i.e., just before making a mad dash up a branch.

I don’t know what this frantic chasing up and down branches is all about, but I did notice that the red squirrels run toward birds in these same branches that have just come back from the feeder with a seed or a peanut.  Maybe they are hoping the birds will drop whatever they are eating and fly off, leaving the tidbits for the squirrels to find?

How do birds predict the weather?

I’ve noticed that the frenzied feeding activity at bird feeders (see yesterday’s post on “finch feeding frenzy“) usually coincides with a precipitous drop in temperature the next day, but I’ve wondered what enables birds to predict that occurrence.

house finches and goldfinches

Sure enough, the day after I photographed the finch feeding frenzy, the overnight temperature dropped from 20 F above zero to -10 F below. Moderate winds added to the chill making the effective temperature for us humans about -30 F!  No birds visited this feeder the next morning until later in the afternoon when the sun had warmed the air up to just about zero degrees F.

Cardinals, Blue Jays, Nuthatches, Chickadees, Slate-colored Juncos, House Finches, and Goldfinches all made an appearance at the bird feeder during the morning hours the day before the frigid temperature drop.

cardinal and goldfinch-

Mr. Cardinal didn’t stay long — the finch mob must have scared him off.

white-breasted nuthatch-

Nuthatches zoom into the feeder, pick out a peanut treat, and zoom off, while the finches just sit and gobble up sunflower seeds.

But it’s not the temperature drop the birds are predicting, it’s the drop in barometric pressure. Low barometric pressure in one area means there will be air movement from a higher pressure area, and in the winter, that usually means Minnesota will receive a big blast of frigid Canadian air.

And the data bear this out:  barometric pressure reached a low point at noon on the day of frenzied finch feeding and increased almost 30 mm by midnight the next day, bringing with it bright sunny weather but a 30 degree drop in air temperature.

It seems that birds are the only land vertebrates (with a couple of exceptions) that possess a paratympanic (i.e., next to the ear drum in the middle ear) barometric sense organ, and it is derived from the same hair cells in sharks and their relatives that provide those fish with information about their jaw movement relative to the prey they intend to gobble up.

black-capped chickadee-

Chickadees and Nuthatches go for the high energy peanut treats in preparation for a blast of cold weather.

So, is a 30 mm change in barometric pressure (a little over 1 inch) enough to trigger such a feeding response in my backyard finches?  Yes, it is.  Experimental data on White-throated Sparrows showed that they could detect a pressure change of as little as 10 mm:  when barometric pressure was decreased artificially in a chamber holding migratory sparrows, they immediately began feeding when the lights were turned on; when the pressure was higher (and normal), they became active, preening and hopping around in the chamber, but not feeding.

And why is it just the birds that have evolved this magnificently sensitive sensor?  In addition to predicting weather fronts, the barometric sensor is most useful for maintaining level flight at a particular altitude during migration.

What about mammals, especially humans?  Can we detect changes in barometric pressure?

gray squirrel foraging in a snow bank

Gray Squirrels were out in numbers looking for seed scattered in the snow by the finch mob.  Did they know what was coming the next day?

Only one species of bat possesses a physical sense organ that detects barometric pressure, but mammals, including humans, can sense changes in pressure in their ears, sinuses, sometimes joints, but there is no specific receptor for the sensation.  Rather it is changes in pressure within a confined cavity that elicits the sensation, and not in everyone.

Finch feeding frenzy

The behavior of my backyard birds is often just as telling as the latest weather report.  Judging from the frenzy of activity going on at the bird feeders today, the thermometer must be headed for negative numbers again.

house finches and goldfinches-

There must have been 2 or 3 dozen House Finches and Goldfinches mobbing this feeder in waves.

house finches and goldfinches-

A few waited their turn in the bushes opposite the feeder…

house finches and goldfinches-

Most of the time the birds took turns amicably.

house finches and goldfinches-

But there’s always a bully in the bunch. The red-headed male House Finch at top right tried moving a female House Finch off her perch.  But she beaked him once or twice and he moved away.

house finches and goldfinches-

Moments later, he was over on the left side of the feeder trying to move a male House Finch away from his perch. But he lost that battle, too, and flew away.

house finches and goldfinches-

I never realized how pretty Goldfinches are in flight with their striking black and gold wings.

The finches monopolized the feeder continuously for 10-15 minutes and then disappeared for an hour or two.  Then the frenzy started up once more, but again dissipated.  It must take quite a while to move all that bird seed from their crop and stomach into the lower part of the intestine for digestion.

When it’s too cold to grab a peanut

The porch thermometer read -10 F (-23 C) and there was bright sun in the backyard, but there were no birds and no squirrels present at or under the feeders.  Finally about 10 a.m., the first foragers appeared.  The thermometer had worked its way up to just under 0 degrees F (-18 C), but the wind was blowing, so windchill temps would be well below 0 F.

male northern cardinal-winter plumage

Mr. Cardinal monitored the surroundings while Mrs. Cardinal foraged at the bird feeder.

female northern cardinal

She is finding the discarded sunflower seeds left by the chickadees and nuthatches who pitch them out of the feeder in search of peanuts instead.  The wind is fluffing out her feathers, but also carrying away her body heat.

White-breasted Nuthatch stashing a peanut

This White-breasted Nuthatch is stashing a peanut in a bark crevice, where it will hammer at it until it breaks off pieces it can eat.  I wonder if the crevices are more apparent when they are upside down, or it’s easier to break them up when they come at it upside down????

White-breasted Nuthatch stashing a peanut

After much hammering away, the Nuthatch has reduced the peanut (directly under its beak) to just a small chunk.

White-breasted Nuthatch basking on a cold morning

You know it’s cold when you see a Nuthatch pause for several minutes in its foraging efforts to bask in the sunlight. The bird’s back was directly facing the morning sun.

Black-capped Chickadee

Peanuts are the preferred high-energy foods on subzero days.

Black-capped Chickadee drilling a peanut

The Chickadee’s method of eating the peanut is much different — grasping the nut with its foot, the bird drilled into it to break off small chunks.  But peanuts at -10F must be brick hard, because this bird drilled it over and over and was only able to break off small bits.  After much effort it finally flew off with the nut, perhaps to its roost hole.

American Goldfinch and Black-capped Chickadee

The Goldfinch watched the Chickadee eating a peanut but made no attempt to go find some food for itself at the feeder.

Two birds exhibiting contrasting strategies for surviving harsh winters in the northern temperate climates:  Goldfinches turn up their metabolic furnace to keep their body temperatures stable on extremely cold winter nights; they do this by harvesting fat-rich seeds (like sunflower seeds) and keeping their fat reserves high.  Chickadees are primarily insectivores that do eat seeds in the winter, but typically conserve their internal fuel resources by lowering their body temperatures at night — just in case they need it to find food the next day.

Black-capped Chickadee

The heartiest of little winter birds…Chickadees are survivors!

By noon, the wind had picked up, and the temperature had dropped again, on its way down to an overnight low of -27 F (-32 C), and I didn’t see birds at the feeder for the rest of the afternoon.  I hope they survived overnight!