they’re back…well, some are

Despite cold rainy weather for the past few days, a few of the many migratory bird species that will eventually pass through this area have stopped by the backyard to grab a quick snack.  Rain may have kept them grounded temporarily, but that’s not a bad thing when they need to replenish their fat stores with all the nutritious bird seed and suet lying around for the taking.

White-throated Sparrow-

A White-throated Sparrow showing off its intensely white throat and pretty yellow eye liner. You can tell it’s chilly by how puffed out the bird is.

White-throated Sparrow-

Doing the two-footed scratch to unearth some of the spilled seed beneath the bird feeder.

Foraging behavior in some birds is hard-wired; their neocortex is full of pre-programmed instructions, unlike mammals that rely on a suite of learned behaviors.  The reason I bring this up is that there was a feeder full of lovely, fresh seed four feet above this bird, but rather than fly up there and grab a beak full, it painstakingly scratched through moldy mulch in search of the stray seed some squirrel hadn’t yet found.

Yellow-rumped Warbler (Myrtle's)

Male Yellowrump (Myrtle’s) Warblers found the peanut butter suet I left on a feeder.

In contrast, Yellowrump Warbers seem to adapt quickly to whatever looks edible in the backyard.  They tried out the bird seed, the left-over peanut butter suet, and scratched around in the litter, perhaps hoping to scare up some errant bug.  A few tried flycatching but nothing much was flying around in this damp weather.

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.

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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.

the birds and the bees

In late September, there are far fewer flowers for the bees and birds to visit — the bees to collect those last remaining dregs of pollen and nectar before the snow flies, and the birds to harvest what seed might still be remaining in flowers that bloomed more than two months ago.

Giant Hyssop is a favorite of the bumblebees these days; its profuse blooms always attract a variety of pollinators, especially when the sunshine can get through the clouds to warm up the air a little.

bumblebees-on-giant-hyssop

The bumblebees generally start at the bottom of the flower head and spiral around upward walking over some flowers, poking their antennae into others, and every now and then inserting their entire head into a particular flower to glean whatever nectar lies at the bottom of the floral tube.

bumblebees-on-giant-hyssop

When the bee gets to the top of the raceme, it makes a short flight over to the next one, beginning again at the bottom and working its way up to the top.  

Flower stalks already being worked by one bee seem to be off-limits; there would probably be little nectar left in the flowers in that case.  But every so often, a couple of bees try working the same flower patch…

bumblebees-on-giant-hyssop

Looks like better foraging on the hyssop flowers than this very attractive but apparently unrewarding purple flower that I planted but have no idea what it is.

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bumblebees-on-giant-hyssop-

oops, this one is taken

bumblebees-on-giant-hyssop-

This isn’t a tandem bumblebee hook-up; the one on top (right side up) is actually flying toward the camera, away from the bee that was originally foraging on that stem.

Overlooking this busy bumblebee activity was a mixed flock of Goldfinches, House Finches, and White-throated Sparrows, all of which were much more interested in the seeds left in the wildflower garden than the flowers there.

house-finch-eating-lilac-seeds-

Their bright red color has faded to a rosy hue with the fall feather molt. This little male spent several minutes picking out lilac seeds from dried up remnants of flower clusters.

house-finch-eating-lilac-seeds

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A juvenile White-throated Sparrow watched what the House Finches were eating, but didn’t seem interested.

think spring…

It’s that wonderful time of the year again, when our drab winter world of white, gray, and tan springs to life and finally gets some color again.

falls creek SNA, MN

Spring…when plants literally spring up from rocks

hepatica-falls creek SNA-

Not Hepatica, but Bloodroot — see below.

NOTE added:  The plant identified as hepatica is actually bloodroot (Sanguinaria canadensis.) It’s flowers are much larger than hepatica flowers and each bloodroot flower grows singly rather than in a multi stemmed clump like hepatica. There is an excellent article about hepatica here:  http://www.bedfordaudubon.org/seasons/spring/hepatica01.html

Thanks New Hampshire Gardener and former neighbor Chris Kraft for correcting my error!

song sparrow

A song sparrow singing his heart out

white throated sparrow-

White-throated Sparrows sing “poor sam peabody, peabody, peabody”

american robin

I think this is the bird that wakes us up every morning about 5 a.m.

Finch vs Sparrow

I see that my bird classification skills are sadly out of date.  Today I found out that the Indigo Bunting is grouped with the Cardinals, Rose-breasted and Black-headed Grosbeaks, and Flame, Scarlet, and Hepatic Tanagers.  How confusing!  For some reason, I have always lumped little birds with conical (finchy) bills into one group, when in fact, there are definitely two:  finches and sparrows (and then of course, one can further split those two categories into old world (Europe-Asia) and (New World – Americas), but I won’t go there in this post.

So, here’s the low-down on what to call the little finch-like birds in your garden.  (Like all rules, there are, of course,  exceptions to these generalities.)

1) If the male is brightly colored in his summer plumage but the female duller, resembling the winter plumage, the species is likely to be a finch, e.g., Goldfinch, House Finch, etc.

This male hasn't quite finished decking himself out in yellow and black, but he's close.

This male hasn’t quite finished decking himself out in yellow and black, but he’s close.

Male House Finches really stand out at this time of year.

Male House Finches really stand out at this time of year.

Female House Finches have some nice stripes, but no accent colors.

Female House Finches have some nice stripes, but lack the brilliant red accent colors of the male.

2)  Sparrows of both sexes sport a mottled brown, black, and white plumage that blends in nicely with their preferred grassy habitat.  Only the juvenile (first year after hatch) birds look different than the adult plumage.

This Swamp Sparrow was singing up a storm, but it was hard to locate him among the dead cattail stems and grasses.

This Swamp Sparrow was singing up a storm, but it was hard to locate him among the dead cattail stems and grasses.

Male and female White-throated Sparrows look identical, but the first year birds have brown head stripes and lack the yellow spot above the eye.

Male and female White-throated Sparrows look identical, but the first year birds have brown head stripes and lack the yellow spot above the eye.

3) Typically, sparrows feed mostly on the ground, scratching under the litter for seeds or insects, while finches are more arboreal, searching for food on the seed heads of perennial grasses, thistles, etc.

Even though there is a feeder full of delicious finch seed right above this bird's head, it prefers to look in the grass for fallen kernels rather than perch on the feeder.

Even though there is a feeder full of delicious finch seed right above this bird’s head, it prefers to look in the grass for fallen kernels rather than perch on the feeder.

A photo from last summer illustrates the plumage difference between male and female Goldfinches, as well as their preference for perching on the flower heads to harvest the seed.

A photo from last summer illustrates the plumage difference between male and female Goldfinches, as well as their preference for perching on the flower heads to harvest the seed.

4) It may be difficult to see differences in the shape and size of their bills, but finches generally have a stouter, thicker bills for their body size than sparrows.  That rule seems to work if you compare House Finch bills to those of Swamp Sparrows, but it looks like White-throated Sparrows have a pretty thick bill as well.

As I said above, there are exceptions to every rule…but at least I won’t be calling all seed-eating birds sparrows now without thinking about it first.

Just passing through…

This is the time of year we see birds passing through from their more northerly breeding grounds to some place south of here where the ground doesn’t freeze and the grass might stay green in the winter.  Walking around one of the local reservoirs today, I saw flocks of White-throated Sparrows everywhere, feasting on the grass seed heads.  Of course, when they saw me, they fled to the trees and tried to hide.

The two photos above illustrate the two color morphs of this species:  white and tan.  Both have the white throat and yellow next to the eye, but differ in the color of the stripe above the eye.   They breed throughout Canada and overwinter in the southeastern and southern U.S., but we get to hear their plaintive “poor sam peabody, peabody, peabody” song in spring and in fall as they pass through Minnesota.  Yes, a few of them were singing today, even though it’s the wrong time of year.

The waning daylength has a stimulatory effect on regrowth of the testis in the fall, much like the increasing daylength does in the spring.  And so for a very short period, right about the time the daylength decreases below 12 hours, bird testes secrete testosterone and male birds sing a little.  I even heard some of the chickadees singing a bad imitation of their spring song.

Lots of juvenile sparrows flocked up with the more colorful adults, who probably show them where to find good food.  But they were a pretty bedraggled looking group.  Life is hard when you’re young, regardless of species.

This young Song Sparrow is slightly better looking, but neither youngster had the typical markings of the adult and both were quite a bit smaller than the adults.  Only about 60% of young sparrows survive their first year.

The other fall migrant passing through in great numbers now is the Yellow-rumped Warbler.  This bird is unmistakable in the spring, and you can’t fail to recognize it when you see that flash of yellow rump between the wing feathers.

(photo from Wikipedia)

But in the fall, it takes more than a good look to determine which warbler species it is.  You can just barely see the yellow tinge under this bird’s wing, and a hint of yellow just above his tail.  This is probably a juvenile female.

This bird makes it a little easier to identify, with the yellow rump clearly visible.

Going out to look for birds is always fun if you can figure out what you have seen.  I have a fabulous new field guide for North American birds.  If you like birds and have an iPad or and iPhone, there is an app for the Audubon Field Guide that has multiple photos of the species (instead of drawings), songs, and even an “eBird” feature that allows you to look for places near you where various species have been spotted recently.  A great investment for $4.99.