an unexpected visitor

Back when we had sunny days a couple of weeks ago, I found a lone Pelican resting at the edge of the Grass Lake marsh.  What was it doing here, all by itself?  Why was it so sedentary, just sitting for hours on the dead cattails?  I guess I’ll never know, but the bird has since disappeared.  Other visitors speculated that it was sitting on a nest — nope, I verified that when it stood up.  Some thought it might be injured and couldn’t fly away. That’s possible, since it was so sedentary, and it did look like one wing was sort of droopy.

White Pelican-

Just sitting, enjoying the early morning sun

White Pelican-

Yawning, stretching, and finding a new sitting position. No nest under its body, and I wouldn’t think the Pelican would try to nest out in the open like this all by itself.

White Pelicans, once rare here, now choose the shallow prairie pothole lakes in western and southwestern Minnesota to breed.  They have rebounded dramatically from a complete absence of nesting birds over the period from 1878 to 1968 to over 20,000 nesting pairs in Minnesota currently, largely due to the conservation and management efforts of the non-game wildlife staff in the MN Department of Natural Resources.

White Pelicans typically migrate from their winter headquarters in the gulf to Minnesota lakes in early spring (March).  It’s a welcome sight to see them in formation overhead, white bodies and wings outlined with black wing tips soaring overhead.

white-pelicans flying-

white-pelican-flying

white-pelicans-flying-

White Pelicans at Pelican Lake, Minnesota photographed in April 2014.

Pelicans are highly social and nest in large aggregations.  They live and hunt communally, using teamwork to scare up and harvest fish from the surface of the water. A single Pelican foraging for itself, like the one I found at Grass Lake, might be far less effective in gathering food.  I hope it recovered and flew off to join its friends somewhere on a distant lake.

Birds that buzz…

Two words that are usually said together:  bird song, or better yet songbirds, those usually small birds in your garden that produce the wonderful, lilting, sometimes piercing, often warbling, unique collection of notes that identifies each species.

But not all songbirds sing, or sing exclusively — some of them have adopted a buzz as part or all of their song. In fact, their soft buzzes or wheezes are remarkably similar and difficult to pinpoint when looking for that buzzing bird that you’re not really sure isn’t some sort of insect.  Why would male birds want to buzz instead of sing?

Take the Blue-winged Warbler for example; wouldn’t you assume from its name that its song would be a melodious warble, rather than a two-note “bee-buzz“?

blue-winged warbler-

A beautiful Blue-winged Warbler sitting out on the edge of the forest overlooking a prairie grassland, buzzing away.

blue-winged warbler-

A better look at the blue wing of the Blue-winged Warbler. He was little and mighty far away.

Just 20 feet away, a Clay-colored Sparrow is buzzing away, with a very similar, low frequency, raspy buzz call.

clay-colored sparrow-

Pale-colored, but with distinctive stripes on its head and face, the Clay-colored Sparrow blends in well to its usual background of dry grass.

clay-colored sparrow-

Its pink bill resembles that of a Field Sparrow, but its buzzing “song” makes it easy to identify.

Buzzing seems to be a common characteristic of “song” in grassland birds, like Grasshopper Sparrows and Savannah Sparrows.  So, one wonders if these birds are trying to avoid detection in prairie habitat by mimicking insects when they “sing”, or whether female birds just find buzzing particularly enticing?

It turns out that buzzing sound made with the bird equivalent of a larynx (called a syrinx), is actually quite physically challenging, and therefore could be an indicator to females of the quality of a potential mate.  German researchers* found that larger, more robust male Nightingales incorporated more buzzes in their song, and enjoyed greater attention from females than their less robust or younger competitors.

Another possible explanation for buzzing birds found in grassland habitats is that low frequency buzzing notes apparently carry long distances, and can be heard throughout and beyond the male’s territory.  Banded Wrens incorporated more buzzing notes in their early morning song that was directed toward other males in the nearby vicinity, at times before females were present.**

*Citation: Weiss M, Kiefer S, Kipper S (2012) Buzzwords in Females’ Ears? The Use of Buzz Songs in the Communication of Nightingales (Luscinia megarhynchos). PLoS ONE 7(9): e45057. https://doi.org/10.1371/journal.pone.0045057

**Citation: P.L. Trillo and S.L. Vehrenkamp. Anim Behav. Song types and their structural features are associated with specific contexts in the Banded Wren. 2005 Oct; 70(4): 921–935. https://dx.doi.org/10.1016/j.anbehav.2005.02.004

the underwater hunter

Quite by accident, while I was out in the Grass Lake marshes looking for the ospreys that should have been near their platform nest (the one usurped by a Canada Goose), a lone Common Loon popped up right in front of me.

Common Loon-

The morning had the perfect kind of filtered sunlight to bring out all the “color” in this black and white bird. For example, I’ve never noticed before how just the right angle of light turns the usually dark feathers below its white necklace into a turquoise band.  The loon’s head feathers are actually faintly iridescent.

During the breeding season, both male and female loons have brilliant red eyes, which might well be an indicator of their readiness to mate.  But loons are fiercely territorial and protective of their chicks, driving off other loons or intruders (like Canada Geese) far larger than they are, and it has been suggested that their red eyes are a threat advertisement of their presence.

Common Loon-viewing fish underwater

The loon frequently dipped its head below the water while paddling around.  It looks like a snorkeler checking out underwater life.

Common Loon-

Several times, following a bit of snorkeling, the loon would quickly dive below the surface, never making a sound or a splash.  I never saw it bring up a fish to swallow, but loons often swallow their smaller prey while underwater.

The Common Loon, or Great Northern Diver, as it is known throughout its range in Eurasia, has some unusual anatomical adaptations for its underwater life:

  • solid, instead of the hollow bones that characterize most birds, decrease the bird’s buoyancy in water and allow it to sink quickly during a dive
  • legs are placed so far to the rear of its body, loons can’t stand up on land, but must push themselves forward on their belly
  • rather short wings decrease drag as the bird propels itself through the water, but the trade-off is that reduced lift provided by the wings requires a long space for taking off into the air

But how does a bird that depends on its eyes for hunting underwater see both in air and in water?  Some have suggested that the birds’ third eyelid (nictatating membrane) which usually has a protective function, is more transparent in loons and other diving birds, and acts like a pair of goggles to preserve an air space between the pupil and the water.  Check out the video below for a good illustration of the underwater swimming activity of these unusual birds.

Common Loon-

She did it!

Yes, Mother Goose did it, at least I’m going to believe she did.  Mother Goose was gone from the osprey nest platform, but there were some brand new goslings in the pond at the base of the tower at Grass Lake.  Somehow four little fluffy ducklings, looking recently hatched, may the ones that survived the plunge down to the pond and are now happily swimming around with their parents.Canada Goose family-

Canada Goose family-

Canada Goose family-

Father Goose watches protectively as a rather hungry hen munches on grass and the goslings explore dirt and possibly eat some bugs.

Canada Goose family-

Canada Goose family-

See you later…

an unusual sighting

For the past several years, a pair of ospreys have raised 2-3 chicks each year at the local marsh that surrounds Grass Lake, using a high nest platform erected specifically to entice them to breed there..

osprey-pair

The pair of Ospreys on their nest platform in June, 2016.

But this year, they must have arrived a little later than usual, because an interloper arrived first to claim the 50 foot high platform for her own nest.

canada goose-on osprey nest

It looks like Mother Goose tidied up the stick nest, before adding her own downy breast feathers to the nest cup.  Although her nest is well protected from danger of flooding on the osprey platform, it is exposed to aerial predators like Bald Eagles that might fly over.  

What is peculiar about this is that Canada Geese usually nest on land surrounded by or near the water on an elevated mound — but not this elevated!

great blue heron-and-canada geese-

While the hen incubates her eggs on her mounded nest, the gander runs protective interference and wards off potential predators or nosy herons.

Mother Goose usually sits tight on the nest, incubating her clutch of 6-8 eggs for most of a month or so, but Father Goose will take over at times so that the hen can stretch her legs and get a bit of food for herself.  Knowing how much space Canada Geese need to land on water or land, I have to wonder how good they are at making a touch down in the limited space of this nest platform.

Once the ducklings hatch, they usually move immediately into the water with their parents.

canada-goose-and-ducklings-1

It’s safer to be in the water because ducklings are vulnerable to a wide variety of predators on land.

Being nothing more than downy balls of fluff, they certainly can’t fly yet, so what will happen to the ducklings raised on an osprey platform?

another muskrat morning

It’s rare (for me) to see a muskrat out and about in the morning, but this one was not at all shy about foraging in a shallow pond right next to the road.  So, lazy me, I just sat in the car and took photos out the window.  What a set-up for nature photography!

muskrat swimming-

munching on tender new shoots

nothing like a good scratch after swimming around in stagnant water…

muskrat swimming-

the way I usually see muskrats — without heads or tails

Muskrats are excellent swimmers, with two layers of fur to protect them from getting chilled, as well as terrific lung capacity that allows them to swim underwater for 15-20 minutes at a time.  They sort of resemble a cross between a beaver and a rat, but the naked (scaly) tail is compressed side to side (vertically) rather than top to bottom (horizontally) like the beaver’s.

Despite having webbed hind feet, muskrats use their tails for propulsion while swimming, and happily chug along at 3 mph or so through their marshy homes. Presumably, the tail is also used as a rudder for steering while swimming, but then you see actions like this.

muskrat swimming-

Muskrats may swim with their tail snaking behind them, but can carry it up above their bodies as well.  Is this for leverage, while the muskrat chews on submerged vegetation?

muskrat swimming-

Swimming along, with its tail in the air.  It did this repeatedly while swimming around this small pond.

So, why does the muskrat elevate its tail while swimming — is it marking its territory, signalling other muskrats, or just waving it in the breeze??

struttin’ his stuff

It’s that time of year when the turkeys parade through the backyard — the Toms eager to show off their fine feathery plumes and the hens picking at scraps from the bird feeder and completely ignoring those beautiful displays of feather finery.

Tom Turkey display-

Seriously, does it get any better than this?  How patriotic, with his red, white, and blue head.  Ben Franklin would be proud!

Tom Turkey display-

He even gobbled a few times for me.  Every tail feather perfect, and with a long beard to boot.  This is some studly male here.

Tom Turkey display-

But look how disinterested the hen is…

Tom Turkey display-

A younger male watching from the wings — observing how this whole display thing is done. He hasn’t developed the neck wattles yet, and he has only a short stubby little snood (that thing that hangs down over the beak).

Tom Turkey display-

Mr. Tom Studly’s head in comparison to that of the underdeveloped youngster.

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.

almost forgotten

I completely forgot about photos taken at Zion National Park on the evening we arrived because they were on a different camera card than all the other photos from the trip. The ladies at the campsite next to ours were enjoying the sunset hour sitting by the creek watching a small flock of Avocets wade in the swiftly moving water.  The birds were motionless for a long period of time until a hiker on the opposite side of the creek started moving upstream toward them, and they took off.

Avocets, Springdale, Utah

Just stopping by in southern Utah on their way to breeding grounds further north…

Avocets, Springdale, Utah

The rusty brown head color is a signal that these birds are ready to breed. Non-breeding birds are entirely black and white. Differences in the intensity of the brown color is most likely a result of the extent of the spring molt in the head and neck feathers.

Avocets, Springdale, Utah

They weren’t ready to move on quite yet, because as soon as the hiker passed by, the birds settled back down on the creek.

American Avocets are one of four species in the world, all of which are easily recognized by their slender, upturned bill which they use to seine back and forth in shallow water for small invertebrates. The rushing creek was most likely a resting spot, not suitable for foraging.

Cardinals mixing it up

In many cases close (geographic) encounters between two different, but closely related, species results in accentuation of their differences — in song, or behavior, or even their distinctive markings.  It’s possible that a female’s choice of mates plays an important part in driving what can often be subtle changes between the two species.  However, in southeastern Arizona, Northern Cardinals (Cardinalis cardinalis) and Pyrrhyloxia, or desert cardinals (Cardinalis sinuatus), are playing a little fast and loose, and it looks like they might be sharing more than habitat.

Before I get to the evidence, let’s review the players in this story.

(1) Northern Cardinals have been expanding their range from eastern North America northward toward Canada as well as southward into the deserts of the southwestern U.S. and Mexico.  Although they tend to stick to the wetter habitats in riparian areas, they often forage and even nest in drier desert habitat, especially where people have been feeding birds, providing lots of seed and bird baths.

male Northern Cardinal-

Most everyone easily recognizes this emblematic, cheery red bird, with its black mask, bright red feathers, and wide, straight, orangey-red bill.  Newly molted male Cardinals have grayer feathers on their back, but the tips of those feathers wear off during the winter, making spring Cardinals bright red all over.

(2) Pyrrhuloxia are less well known, occurring only in the extreme southern parts of Arizona, New Mexico and parts of Texas, as well as most of Mexico.  They prefer the desert scrub and mesquite habitat, foraging for seeds and insects on the desert floor, but will also visit the lusher gardens with bird feeders and bird baths where they no doubt meet up with their close relative, the Northern Cardinal.

male Pyrrhuloxia-

At first glance they look completely different from their cousins, with mostly gray plumage, mottled with red in the face and breast in the male only, a much bigger crest of head feathers which they keep erect unlike the Cardinals, and a yellow-orange beak with a distinctive bend in it.

Cardinal and Pyrrhuloxia -angelamccain.smugmug.com

Pyrrhuloxia and Northern Cardinal males looks distinctly different (photo by Angela McCain, smugmug.com, from Edinburgh, Texas)

female cardinal vs pyrrhuloxia-birdswesee.com

Female Cardinals are a bit browner and the Pyrrhuloxia are grayer overall, but there are distinct differences in beak shape and coloration between the two species.

At the Sonoran Desert Museum in Tucson, a captive adult Cardinal mated with a captive adult Pyrrhuloxia, and hybrid offspring of this original pair now populate the aviary and freely interbreed with one another.  The hybrids share characteristics of both species, with intermediate plumage (grayer than Cardinals, redder than Pyrrhuloxia) and slightly curved beaks.

Cardinal-Pyrrhuloxia hybrid-Sonoran Desert Museum

A Cardinal-Pyrrhuloxia hybrid at the Sonoran Desert Museum has grayer plumage on its back and a slightly decurved upper beak.

The ability to produce viable, reproductively capable offspring means that these two supposedly distinct species, really aren’t different at all!  Differences in their habitat preferences and their former separate geographical distributions probably kept the two “species” isolated from one another.

But an aviary is an unnatural situation, in which partnering mistakes might be inevitable. More important is whether interbreeding in these two closely species has actually been observed in the wild?  Perhaps. Hybrid “Cardhuloxia” have been reported from Baja California, Mexico, and I’m wondering whether there has been some gene sharing going on in southeastern Arizona as well.

Male Northern Cardinal -Portal AZ

This male possible Cardhuloxia hybrid seen in Portal, Arizona, has an unusually long red crest, a much grayer than usual plumage on its back, and a distinctly un-Cardinal-ish song.