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.

adding some color

The landscape may have turned white again with the latest snowfall, but the birds are starting to show some color at last, with the males molting some of their body feathers.

male house finch

I don’t think I’ve ever noticed the pretty red rump of the male House Finch in its breeding plumage.

male american goldfinch-

Not quite ready for prime time yet, but the male American Goldfinches are starting to sprout new yellow feathers in place of their drab tan winter plumage.

Cardinals, Chickadees, and Finches are singing — spring is on its way, if very slowly.

male cardinal-

Even the Cardinals have yet to lose the gray edging of their bright red feathers before they gain their true spring brilliance.

Bird barometer

I can usually tell what sort of weather conditions are coming using my “bird barometer”, which consists primarily of monitoring the intensity with which birds are feeding at the various feeders scattered around the backyard.  About 24 hours before a big thunderstorm or a dreary day with steady rainfall, those feeders are humming with activities of multiple individuals of a variety of species.  For example, yesterday was cloudy but mild, but dozens of finches, sparrows, and chickadees crowded in or around the feeders for several hours in the morning.

white-throated-sparrow-

A flock of a dozen or so White-throated Sparrows searched through the grass and leaves beneath the feeders, often chasing each other away from hot spots where the seed had dropped from the feeders above.

slate-colored-junco-

Mixed in with the Sparrows were a bunch of Juncos, equally intolerant of others foraging near them. Extended chases of a bird that encroached on another’s foraging space was common.

fox-sparrow-

A newcomer to the backyard showed up — a Fox Sparrow.  I’ve seen these birds only rarely, and usually just a brief glimpse as they migrate through MN on their way to their breeding grounds in Alaska or their wintering grounds in the southeastern U.S.  They scratch through the litter beneath dense cover, making them tough to spot.

fox-sparrow-

Fox Sparrows are larger than most other sparrows, with bold breast stripes, a gray stripe above the eye, and rusty red tails and backs. The western US subspecies are slate gray though.

These ground-feeding birds were reaping the benefits of all the spilled seed from the multiple gangs of finches, chickadees and nuthatches vigorously attacking the feeder above them.

house-finch-and-goldfinch

Red splashes of color on the male House Finch and yellow splashes of color on the heads of the Goldfinches — the last remnants of their colorful selves from the past breeding season.

purple-finches-and-house-finch

Purple Finches (male on lower right, female on lower left) dominate the feeder to the exclusion of the slightly smaller Goldfinches and Chickadees.

Today (just 24 hours after the feeding frenzy) is rainy and cold, and the feeders are quiet.  An occasional Blue Jay visits, but even the Chickadees are absent.  How do birds predict such changes in the weather?  Do they really have an internal barometer?

In fact, they do.  A group of hair cells in the Vitali Organ, or Paratympanic Organ (named for Giovanni Vitali who discovered them about 100 years ago) in the middle ears of birds is thought to be responsible for detecting changes in atmospheric pressure of just 10-20 mm of water (about 0.75-1.5 mm of mercury).  Such exquisite sensitivity allows birds to maintain their elevation while flying long distances within 10-20 feet of desired altitude — essential for navigation, but it also allows birds to sense changes in barometric pressure at ground level, especially the declining barometric pressures that signal approaching storm fronts.  Input from these specialized cells due to barometric pressure changes then causes abrupt and marked changes in bird behavior, as they prepare for and protect themselves from changes in the weather.

Are birds the only animals with this unique ability?  Hardly.  Most animals can sense impending changes in the weather, using a variety of other cues (infrasound, daylight, smell (ozone?), static electricity, etc.).  But only one group of mammals may possess the type of middle ear barometric pressure detectors present in birds.  Can you guess what group that might be?

An interesting reference on this subject can be found here:  Von Bertheld and Gianessi, 2011. The Paratympanic Organ:  A barometer and altimeter in the middle ear of birds? Journal of Experimental Zoology 316 (6): 402-408.

Seed-eater’s Paradise

There is quite a banquet of tasty choices for seed-eaters in the backyard these days, with all the wildflowers trying to set seed.  Goldfinches have been attacking the seed heads of the cup plant, tugging forcefully to loosen the seeds that are packed into a dense head.  More than a dozen male Goldfinches chirped and chittered as they tore into the plants.

goldfinch feeding on seeds

Apparently it takes quite a bit of tugging force to dislodge the seeds packed tightly into cup plant seed heads.

goldfinch feeding on seeds

The technique is simply to tear off the outer leafy material exposing the seeds within.

goldfinch feeding on seeds

Got it out, now what?

goldfinch feeding on cup plant seeds

The bird turned the seed around and around in its mouth, like it was tasting it, and then dropped it and went on to another seed head. Maybe this one wasn’t ripe enough?

goldfinch feeding on bee balm seeds

Other male Goldfinches explored the seed heads of the bee balm (Monarda).

goldfinch feeding on bee balm seeds-

There is a good crop of these in the backyard as well, and each seed head produces a lot of seed.

goldfinch feeding on seeds

And of course there is coneflower seed for dessert.

transforming…

Spring is a time of change in many ways.  Over the past couple of weeks, I’ve watched the goldfinches (males, mostly) transform from the drab tan and gray winter plumage into their bright, golden, summer one.

american goldfinch male-

This male is just beginning the molt.

The process is rather gradual — growing feathers is an expensive and time-consuming process — and consequently, male Goldfinches in the spring exhibit variegated colors.

american goldfinch male-

The black feathers on the head are still coming in, but the body feather molt is almost complete on this male.

Like many songbirds, Goldfinches undergo two feather molts annually:  a complete body, wing, and tail molt in the fall, and a partial molt of just body feathers in the spring before breeding.

american goldfinch male-

Spring molt complete, this handsome fellow is ready for action.

The yellow color comes from dietary carotenoid pigments, which must be consumed while the feathers are coming in.  (Read more about pigment coloration in birds here.)  Millet seed provides much higher concentrations of carotenoids than sunflower and thistle seed (which are quite low), so perhaps Goldfinches change their diet slightly in the spring to increase their carotenoid uptake.

Studies have shown that the male Goldfinches that are brightest in color are the most successful in attracting a mate and have the highest levels of carotenoids circulating in their blood, which might be attributed to their greater success in seeking out the appropriate food sources.

Surviving the cold — part I

Even though I’ve just read that 2015 was the hottest year in historical weather record-keeping (2 degrees F above average world annual temperature), the backyard here is buried in the deep freeze.  Several of my fellow bloggers have been posting queries about how animals survive conditions like this in the wild — or how humans who live and work outdoors all winter survive these extremes.  So, being somewhat of an expert on this topic once upon a time, I’m going to try to explain how they do it.

goldfinch-winter chill

Yikes — it’s chilly out there. for this young American Goldfinch

First — the challenges of winter at far northern latitudes:

  • low temperatures mean warm-blooded animals need to turn their heat producing furnaces to high to offset heat lost to the environment
  • wind, sleet, and any precipitation carry body heat away even faster than just being surrounded by cold air
slate-colored-junco

Who ordered this sleety, icy rain?  But Slate-colored Juncos are tough, and they outlast this kind of inclement weather.

  • the sun is low in the sky and it’s often cloudy and overcast, so radiant heat input is hard to come by
  • where’s the food?  Summer production is long past, food is buried under snow, other animals got to it first — so how does a warm-blooded animal get enough energy daily to fuel the heat-producing furnace?
white-tailed-deer-in-snow-

Really, there isn’t much here to fuel the needs of a large-bodied animal like these White-tailed Deer.

Solutions:

1. Prepare for it:  Those chilly fall mornings and waning daylength are signals that challenging days are ahead.  Animals prepare for the challenges of winter by hoarding or stashing food in places where they can find it later. Usually, there is a flurry of activity at bird feeders as birds and squirrels take seeds to their winter roosting sites.

chipmunk

Packing those cheek pouches full, a chipmunk carries his prize underground to eat later.

And — a new set of freshly molted feathers in the fall not only disguises once brightly colored birds, but provides a nice, new downy coat of insulation.  An under coat of dense fur beneath longer guard hairs helps keep mammals warm in the winter.

2. Eat like crazy — in order to put on a nice layer of fat reserves.  This strategy works better if you’re a fleet-footed mammal, because when birds put on too much fat, they can’t fly.  In addition to the insulative value of a layer of fat, it does provide an energy reserve for overnight energy expenses and the days when foraging for food was inadequate.

house-finches

Dining with friends (House Finches) is always a good idea, so that many eyes can spot the skulking predators.

common-redpolls-

Pine Siskins are so good at searching out and consuming high volumes of seed per day that they can maintain their body temperatures, even at very low extremes.  Like Common Redpolls, these little birds are champions at cranking up the metabolic furnace to generate heat.

And — since there aren’t many insects active in the winter, avian insectivores like chickadees switch their diet to take advantage of the high-energy content in seeds.

black-capped-chickadee

Do you wonder how a bird that weighs less than a McDonald’s ketchup packet stays warm in sub-zero cold weather?

3. Hide from the worst extremes:  Chickadees, nuthatches, and woodpeckers find a refuge from extreme temperature and wind in a roost hole.  Some sparrows and larger birds like Robins and Blue Jays huddle in the thickest part of evergreen vegetation which protects them from the effects of wind and precipitation.  Many mammals retreat to underground burrows, tree cavities, or leafy nests to hide from extremes.

bear-in-den-illustration (nps.gov)

Below ground, temperatures are above freezing, and mammals are protected from wind and precipitation. (Illustration from http://www.nps.gov/katm/blogs/Bear-Hibernation.htm)

To be continued tomorrow with more solutions….

white-tailed-buck-in-snow

Hidden treasures

Goldfinches are among the strictest vegetarians in the bird world, selecting an entirely vegetable diet and only inadvertently swallowing an occasional insect.” (says the Cornell Lab of Ornithology — about the diet of the American Goldfinch.)  In fact, (the Cornell website suggests), cowbird chicks that hatch in a Goldfinch nest often starve presumably because they can’t digest the highly vegetable diet the parents bring to their own young.

I often observe Goldfinches foraging in the flowers of the Cup Plant, which form a 7-8 foot tall border on one side of my wildflower garden.  I always assumed they were harvesting seeds from the spent flower heads, but that was definitely not the case for one Goldfinch that I watched.

goldfinch foraging on cup plant

A male American Goldfinch spent many minutes probing the bases of unopened flower heads in the Cup Plants.

goldfinch foraging on cup plant

The bird examined the base of the unopened flowers closely.

goldfinch foraging on cup plant

Sometimes I could see tiny spiders or ants crawling around, perhaps trying to avoid being ingested by the bird.  It sure looks like this bird is about to ingest one.

goldfinch foraging on cup plant

The bird went to great lengths to check out those unopened flowers.

goldfinch foraging on cup plant

All this attention to this particular place on the flowering stem must mean there were some hidden treasures there.

So I pulled apart a few of those flower heads myself, and discovered a treasure trove of insect material.  Ants, spiders, tiny mites, and…a web of plant material covering a 1/2 inch long larva right at the base of the unopened flowers.  This might be unusual behavior for a Goldfinch to harvest insects in this way, but it would certainly be beneficial to provide a little animal protein for their rapidly growing offspring.  Perhaps, the “inadvertent swallowing of insects” isn’t really so inadvertent as was once assumed.

the singer, the squawker, and the silent partner

I carried the big telephoto around for several hours yesterday, visiting several locations at which I had previously seen quite a few warblers, but I came up with a very short list of birds.  The resident orioles, song sparrows, goldfinches, cardinals, and even catbirds were quite obliging — all singing away, but the warblers (except one you’ll see below) were sadly absent.

The best and most persistent singer of the bunch was the Yellow Warbler, a bird fond of willows and low shrubs, where it usually advertises its presence in a bold manner by shouting out “here I am — aren’t I beautiful?”

yellow warbler

At least the bird was in front of the sticks, instead of behind them…

yellow warbler

And yes, this was a particularly handsome male Yellow Warbler, who is looking a bit chubby from those fluffed out feathers.  It was a cold. windy morning.

The Squawker was an Eastern Kingbird, who sat on an eye level branch about 50 feet away, giving me the once over. But the bird was not shy about diving after an insect or two and then returning to exactly the same branch.  I took at least 20 nice photos, but only one in which the bird opened its mouth to give its characteristic buzz-squawk call.  The Cornell Lab of Ornithology has several recordings of the pleasant songs Kingbirds sing — but perhaps this was a female, or  a non-territorial male.

eastern kingbird

“buzz-squawk” — feathers all fluffed out to keep warm, even tucking them over its bare toes.

eastern kingbird-

Good looking in any position.

American Goldfinches males are usually vociferous singers, loudly proclaiming their breeding status to all around them.  I must have gotten too close, because he half-turned, looked shyly away from me, and then made a dive for cover in the nearby bushes.

american goldfinch

This bird had nothing to say — he was all looks and no voice.

Better luck next year…maybe the warblers will stop in for a day or two then.

Bees, birds, and butterflies

The wildflower garden was really “humming” with activity this morning. Perfect weather combined with maximum bloom of the wildflowers has drawn a variety of wildlife in.

wildflower garden

The scene on a mid-August (feels like fall) morning.  You can’t see them in this photo, but there are dozens of bees, mostly bumblebees, working the flowers.

tiger swallowtail butterfly on obedient plant

At least two and possibly three Tiger Swallowtail butterflies roam the various flowers looking for the best nectar supplies.  This one seemed to enjoy the Obedient plant nectar.

ruby throated hummingbird on cardinal flower

Ruby-throated Hummingbirds are back, just as the Cardinal flower has reached maximum bloom. They actually seem to prefer the flower nectar over the sugar water in the HB feeder.

goldfinch-male-and-female-pair on cup plant

And of course, the Goldfinches are everywhere, picking off the seeds from all the flowerheads.

goldfinch-on-gray-headed-coneflower

They don’t like the Black-eyed Susan as much as the Cup Plant (above), but any composite flower will do for these guys.

A surplus of yellow

After looking at the hundreds of photos I took over the last few days, I have come to the conclusion that yellow is a very popular color in the bird world.  Is this because of the evolutionary relationships of the many yellow warbler species, or is it the availability of carotenoid-containing foods that produce the yellow and red colors in birds, or is yellow simply a highly desirable color in the bird’s eye?  A Google search yields no answers.

Here are a few of my yellow favorites from past few days:

Against a dull background of leafless trees, the American Goldfinch really stands out.

Against a dull background of leafless trees, the American Goldfinch really stands out.

Chestnut-sided Warblers have brilliant golden yellow helmets.

Chestnut-sided Warblers have brilliant golden yellow helmets.

A Magnolia Warbler lights up the green foliage he tries to hide in with his yellow breast.

A Magnolia Warbler lights up the green foliage he tries to hide in with his yellow breast.

Nashville Warblers comb the underside as well as the topside of the foliage.

Nashville Warblers comb the underside as well as the topside of the foliage, showing off an entirely yellow breast and belly.

The female Northern Parula Warbler shows off an unusually rich yellow throat color.

The female Northern Parula Warbler shows off an unusually rich yellow throat color.

A very cold little Blue-winged Warbler has puffed up his yellow feathers to stay warm during these last couple of chilly days.

A very cold little Blue-winged Warbler puffed up his bright yellow feathers to stay warm during these last couple of chilly days.

A Yellow-throated Vireo sedately waits on a branch until I can take its photo -- unlike those pesky warblers that flit.

A Yellow-throated Vireo waited sedately on a branch until I took its photo — unlike those pesky warblers that flitted around continuously.

Great Crested Flycatchers are not only larger than most other flycatchers but show off their lemon yellow bellies.

Great Crested Flycatchers are not only larger than most other flycatchers but show off gorgeous lemon yellow bellies.