Endless Spring

Summer? Says who? For this White-rumped Sandpiper, this is still the season of spring migration.

From the middle of a flooded field in northern Ohio, Kenn writes: After a totally crazy month, the calendar has just clicked over from May -- we call it May-hem around here -- to June. So what season is it now? If you’re a White-rumped Sandpiper, it’s still spring, still the height of northward migration season.

Of course, if you’re a White-rumped Sandpiper, you’re probably not reading this blog.

If you’re a sandpiper, you’re too busy to read things like this. Especially if you’re a White-rumped. More than three dozen different species of sandpipers are found regularly in North America; all of them are at least somewhat migratory. None of them migrates north later in spring, on average, than the White-rump.

This bird has a lot of distance to cover. Its wintering sites are all in southern South America, including some as far south as the tip of the continent -- or even farther: this amazing migrant has even been recorded in Antarctica. Its nesting sites are all in high Arctic regions of Canada and Alaska, most of them north of the Arctic Circle. So when northbound birds get to the latitude of the lower 48 states, they still have some traveling ahead of them. It’s amazing how late in the spring they show up. When I was down in Texas at the beginning of May this year, I saw a few White-rumped Sandpipers, but they were among the earlier arrivals at that location, and most would be passing through in mid-May. Here in northern Ohio, White-rumps have just shown up within the last few days. Their peak passage through here will be during the first ten days of June. Their time on the Arctic tundra may be very brief: some adults, perhaps those that have failed at their nesting attempt, will be southbound before the middle of July.

See the obvious white rump on this bird? No, we can't see it either.

Birders often overlook the White-rumped Sandpiper. That may be partly because of its migration timing, slipping through after many birders have given up on spring. It’s also partly because it’s a subtle bird with few obvious field marks. Looking at the photos here, do you see any white rump patch? The bird’s namesake field mark is visible only in flight, or rarely while the bird is actively preening its feathers. Various field guides, from the second edition of Peterson’s western to some editions of the National Geographic, have illustrated this species with its wings drooped, showing off the white patch on the rump and uppertail coverts. In real life, the birds just don’t stand that way. When I see this species in spring, I usually pick it out first by its squeaky callnote, by the fine sharp streaks on the chest, and especially by the long-winged profile. Those long wings, incidentally, are a reflection of the bird’s long-distance migration.

I doubt that we can have the bird’s name changed to "Invisibly-white-rumped-and-uppertail-coverted Sandpiper," but if we called it "Long-winged Sandpiper," birders might overlook it less and appreciate it more.

Regardless, if you’re anywhere east of the Rockies, especially in the interior of the continent, early June is not too late to see the White-rumped Sandpiper in spring migration. Singles and small flocks are stopping over in all kinds of shallow wetlands, from the edges of grassy marshes to flooded farm fields. If you can find one of these subtle sandpipers, give it a salute of respect for the 8000-mile journey it has undertaken, and wish it success in getting to the tundra on time.

The Finch Forecaster

From northern Ohio, Kenn writes: This Common Redpoll was outside our window a year ago, in December 2007. It was one of dozens that came to our feeder that month, and one of hundreds that we saw in the general area. This month, we haven’t seen a single one.

Redpolls are in the "winter finch" group, and they were the headliners last year. Common Redpolls (and a few of their pale high-Arctic relatives, Hoary Redpolls) were all over the central and eastern U.S. and southern Canada in the winter of 2007-2008. Pine Grosbeaks also moved south in good numbers. So did Red-breasted Nuthatches and Bohemian Waxwings, which are not finches but which are similarly erratic in their winter occurrences.

We used to talk about winter finch invasions being "unpredictable," but that’s not accurate. These invasions are caused by changes in the supply of natural wild food in the boreal forest of Canada and Alaska, and if we knew enough about what was happening there, we could make predictions about which finches would invade in a given winter.

In fact, there is someone who knows enough, who researches the situation every year and makes predictions about the finch flight. The dynamic duo of field ornithology in Ontario, Ron Pittaway and Jean Iron, are very well connected with scientists and birders all over the north. Every year in early fall, Ron Pittaway collects info about seed crops in the boreal forest and writes a prediction, focused on which birds will have a flight in southern Ontario and adjacent regions. All of us in the surrounding states and provinces wait eagerly for Ron’s forecast.

Knowing how tricky it is to gauge these things, it’s amazing how often Ron Pittaway is right on the mark. For the 2007-2008 winter, he predicted the big redpoll flight and the movements of Pine Grosbeaks, Bohemian Waxwings, and Red-breasted Nuthatches. For this winter, he predicted that Pine Siskins would mostly leave Ontario, and indeed we had a flood of them coming south through the Midwest this fall. He predicted the possibility of a widespread southward flight of White-winged Crossbills, and we’re all enjoying the reality of that now.

Does Ron have mystical powers? Well, yeah, but this is mostly just a result of detailed understanding of the birds and their food supply. This year, for example, Ron predicted that Pine Grosbeaks would stay in the far north because the mountain-ash berry crop was good there. He predicted that Pine Siskins would leave Ontario because the spruce cone crop was poor in that province. He predicted the White-winged Crossbill flight because spruce cone crops over much of Canada had fallen off from previous highs. It’s fascinating stuff; you can read the whole thing on the Ontario Field Ornithologists site here.

Never again would birds' song be the same

From Oak Harbor, Ohio, Kenn writes: It isn’t often that ornithologists get to document an abrupt change in the song of an entire species of bird, but this is exactly what happened less than four years ago.
Moreover, it happened with a very common bird, the White-throated Sparrow. This beautifully marked native sparrow nests across the eastern two-thirds of Canada and parts of the northeastern United States, winters commonly in most eastern states, with small numbers throughout the west. It’s a backyard bird for literally millions of bird watchers. You would expect that a sudden change in its song would command the attention of legions of birders. But as far as I know, only one reference book has documented this change in vocal pattern.

That reference (I must admit) was my own field guide. It was published in 2000 as the Kaufman Focus Guide to Birds of North America, with a brightly colored cover featuring a Scarlet Tanager. In 2004, however, the marketing department at the publishing company decided that they should change the name of the series from Kaufman Focus Guides to Kaufman Field Guides. So they designed a new cover, the current one that features a bright Yellow Warbler on a white background, and it was issued in early 2005.

I insisted that if we were going to change the cover design, I had to make some improvements to the interior of the book as well. They didn’t want me to do a complete revised edition (and besides, we were busy with the Kaufman Field Guide to Insects), but they said I could make essential changes: adding 8 pages to the introduction, improving a few illustrations, updating some maps, changing some scientific names to conform to the latest pronouncements of the American Ornithologists’ Union. And making an important change to the description of one bird’s voice.

If you find yourself in a position to compare the editions of the focus / field guide, look up the White-throated Sparrow. In the older edition it’s on p. 350, and its song is described as Oh, sweet, Canada-Canada-Canada. In the newer edition, White-throated Sparrow is on p. 358, and its song has changed to Oh, sweet, Kimberly-Kimberly-Kimberly.

Sorry, Canada, but those are the facts.

This morning Kim called me to the window. In the garden was a White-throated Sparrow, foraging on the ground, crisp and bright among the new frost. It had not been there the eve before, and this seemed a gift of this special day, as if song or laughter had carried it aloft and placed it here. The bird wasn’t singing but in my heart I could hear it anyway.

Antarctica, Day Two: I.D. At Sea

From home base, Kenn writes: (now that I've been so cutely interrupted by Kim's last post ... That's the thing about Kimmer, I can't stay mad at her for more than a few seconds at a time.) On January 8, when I got out on deck around 5 a.m., we had left the Beagle Channel itself but the islands of Tierra del Fuego were still visible off the stern. Dozens of Sooty Shearwaters and Greater Shearwaters, plus various other seabirds, were around the ship. The last of the land soon disappeared behind us but we would continue to see large numbers of seabirds all day. Most seabirds are beautiful creatures and amazing masters of flight, and in addition, many of them present fascinating challenges in identification.

Check this out. I know you can’t see much detail, but this is an unaltered photo taken from the rail of the upper back deck of the ship, with six seabirds captured in the same frame. From left, they’re a young Wandering Albatross, a Brown Skua, three Greater Shearwaters, and a Northern Giant-Petrel. I’m not saying every moment was like this, but it was common to have 30 or 40 individual birds visible at once.

Watching birds here was good practice for identifying them back in North America. This Wilson’s Storm-Petrel nests only on islands in the far southern oceans, but it’s common in the northern summer off the Atlantic Coast of the U.S. and Canada, and scarce off the coast of California.

Greater Shearwater is another bird we can see close to home in the northern summer. At that season it’s common off the Atlantic Coast of the U.S. and Canada, but it nests only on islands in the South Atlantic.

Identifying seabirds can be tough, partly because the viewing conditions at sea can be challenging, partly because the differences can be subtle. Even on very large seabirds, the best field marks can involve small differences. Take a look at this Southern Giant-Petrel ...

... and then at this Northern Giant-Petrel. Both species are variable in plumage, and the best way to tell them apart is by the color of the tip of the bill: green on the Southern, red on the Northern. Those who are red/green color-blind, as some excellent birders are, might note that the Northern's bill tip looks darker than that of the Southern. (These are poor names, incidentally, since both species live only in the Southern Hemisphere and their ranges overlap extensively.)

Variation reaches an extreme in the beautiful Wandering Albatross. It has five distinct populations, nesting on different island groups, that are thought by some to be separate species. All of them vary at least a little with age, so there are a vast number of different plumages possible on these birds. Add to that the fact that Royal Albatross can be very similar to Wandering, it has two distinct populations that also might be separate species, and it also varies with age. The richly colored brown bird above is one of the youngest Wandering Albatrosses.

This bird, extensively white above, is an older Wandering Albatross and may be an adult male, although some old males can become even whiter than this (and some adult females might duplicate the appearance of the bird in the photo).

This partially brown bird is in the Wandering Albatross complex and is almost certainly a young bird, although there are a few populations in which even the adults show a lot of brown. We saw many such variations today, and enjoyed discussing the identification of all of them.

Fortunately, we often got to look at Wandering Albatross individuals from very close range!

For this voyage, Victor Emanuel Nature Tours (VENT) had filled 85 of the 110 spaces on the Clipper Adventurer. You can’t have 85 participants and only one or two leaders, so VENT had recruited a team of leaders, all of them long-time friends of mine, starting with Victor Emanuel himself. Victor has been a friend of mine since the mid-1970s, when I was a teenager and he hadn’t yet started his tour company. Also along as leaders were Barry Lyon, a seasoned world birder and one of the professionals in the VENT office; Louise Zemaitis, great all-around naturalist, teacher, and nature artist; Michael O’Brien, a bird identification expert and lead author of The Shorebird Guide; and Lars Jonsson, from Sweden, probably the most renowned bird painter in the world today, and a leading authority on bird identification as well. Dr. John Fitzpatrick, director of the Cornell Lab of Ornithology, was supposed to have been a leader on this trip, and at the last minute he was unable to go. In his place, he sent Brian Sullivan, head of Project e-Bird for the lab, and another expert on bird identification, especially seabirds. Finally, the ship’s ornithologist, Geoff Carpentier from Canada, was also on deck, taking part in the discussions of identification from the perspective of his experience in these waters.

So a day at sea, looking at challenging or tricky seabirds, turned into a wonderful ongoing discussion and series of impromptu seminars in birding. For me, with my long-time interest in advanced bird identification, and for Kim, who is interested in all of these things and who was seeing some of these southern seabirds for the first time, this was a day of total fascination. Some people might imagine that all those hours on the open ocean could become boring, but for a birder, nothing could be further from the truth.

BTB

From Oak Harbor, Ohio, Kenn writes: It’s an awfully small bird to have such a big name. The Black-throated Blue Warbler is maybe five inches long from the tip of its bill to the end of its tail. It weighs less than an ounce, even when it’s fattened up for its biggest journey of the year, which is happening right now. This warbler is on its way south, and by this date in late September, most of its kind have already headed to more southerly latitudes.

Birders and non-birders could be separated on the basis of their experience with warblers. Everyone has seen birds like geese, and everyone notices pelicans or eagles if they’re arround. But warblers are different: they mostly go unnoticed by most people, even while many birders regard them as favorites. North America has more than 50 kinds of warblers – small, active, colorful birds that flit among the leaves, feeding on insects. Most of them spend the winter in the tropics, coming north in a rush in spring, while birders rush out to look for them. Their southward migration in fall is not so celebrated, partly because many of them change into a duller fall plumage, making them harder to tell apart. But the male Black-throated Blue Warbler has a black throat and a blue back all year long.

Every species of warbler has its own distinct range. This male Black-throated Blue, which paused out behind the Black Swamp Bird Observatory in northern Ohio today, probably had come from somewhere in southern Canada, and it was almost certainly headed for wintering grounds somewhere in the Caribbean. Once when I was in Jamaica in winter I was amazed at how many Black-throated Blue Warblers I saw in the woods. These little migratory birds represent a shared treasure, to be enjoyed by citizens of several nations on their seasonal travels.

Happening Right Now: Crossbill Invasion

From Birding Central, Kenn writes: In the northeastern quadrant of the U.S. and adjacent southern Canada, this is shaping up to be a huge winter for northern invaders. I’ve written already about Pine Siskins invading southward, and that push is continuing, with flocks reported all over the east. Northern Shrikes have appeared in unusual numbers, and so have Snowy Owls, with many around southeastern Canada and the Midwest. Flocks of Evening Grosbeaks have put in brief appearances in several places. Now, just within the last few days, flocks of White-winged Crossbills have set the hotlines buzzing all over Ohio.

Of all the "winter finches," White-winged Crossbills are the most nomadic. They specialize on cones of spruces, hemlocks, and tamaracks, using their trademark crossed bill tips to pry open the cones and get to the seeds. The map here shows their overall range in North America -- but they are never present throughout this range at once. They concentrate where there are bumper crops of cones, nesting and raising their young where the food is abundant at practically any time of year. When the cone crop fizzles and the food supply declines, flocks of crossbills fly fast and far in search of the next good feeding area. The purple area on the map shows the limits of their year-round range; within those limits, the same birds might nest in Quebec one year, Alaska the next, Ontario a few months later, sweeping back and forth across the continent to find the cones.

The dashed blue line on the map shows the (very approximate) southern limit of their winter wandering. They certainly don’t come south to this line every year, or even once every five years. The classic setup for an invasion is to have a huge crop of spruce cones in eastern Canada, so that the crossbills nest and raise lots of young, followed by a crash in the cone crop in fall. When that happens, White-winged Crossbills may suddenly appear all over Ohio and surrounding areas -- as they have in the last few days.

A birder who knows the callnotes might detect these birds anywhere, the flocks passing overhead in rapid flight. To get a sit-down look at White-winged Crossbills, birders are seeking out places where northern evergreens have been planted. Parks and cemeteries with lots of hemlocks have been productive here. The crossbills appeared in the Cleveland area last Saturday, in Toledo on Monday, in Columbus today. There are probably hundreds more flying around that no birder has seen yet.

Purple On The Rocks

From northern Ohio, Kenn writes: Okay, the name of the "Purple" Sandpiper is an exaggeration. The feathers just have a faint purple sheen when they're freshly molted, all right? But these birds are impressive for deeper reasons than just their color.

We were reminded of that during our day of birding the Lake Erie shoreline in blizzard conditions on Nov. 18. Kim already told you about our visit to Huron Harbor early in the day (see her post "Extreme Birding"). The highlight of the afternoon came at Headlands Beach State Park, east of Cleveland, where we found two Purple Sandpipers along the breakwater.

The Purple Sandpiper is an incredibly tough creature. Its nesting range straddles the Arctic Circle in eastern Canada, mostly in areas that few birders ever visit. It stays in that freezing Arctic climate until very late in the fall. Then it just comes south to the colder regions of the Atlantic Coast, where it spends the winter scrambling around on coastal rocks that are battered by the waves. On the map here, red is the normal summer range, dark blue is the normal winter range, pale blue is where winter stragglers are seen, gray is where migrants pass through. Notice how much of the winter range is up in Canada -- on the rocky edge of Newfoundland, where freezing spray coats the rocks in wind chills of 40 below zero. Notice also that Lake Erie isn’t on the normal route at all (the text that goes with this map mentions that this is a rare visitor on the Great Lakes). We were cold today while we were watching the birds, but I’ve never been warm while I was watching Purple Sandpipers.

Robert Hershberger spotted the birds first, ahead of us as we were making our way out along the huge jumbled rocks of the breakwater. We stalked them cautiously, but eventually we realized that they were coming toward us! Stunningly unconcerned about our presence, they kept coming closer until they were practically at our feet.


What remarkable birds these were! We could see every detail of their sleek plumage, their stout orange legs, their blunt orange-based bills. Clambering about on the rocks at the very edge of the water, they were sometimes wading belly-deep, sometimes submerged when another wave crashed against the breakwater. We were bundled up in as many layers as we could carry and we were still chilled through, stung by the sleet hitting our faces -- but these Purple Sandpipers, tough and beautiful, seemed oblivious to the freezing blasts. Another tough and beautiful creature, Kim, found that her camera batteries had died in the cold, so she walked back half a mile to the parking lot to get fresh batteries and then stood in the driving wind and sleet and snow to shoot the Purple Sandpipers. Conditions were challenging for photography (slanting lines of snowflakes cross all the images, and in some we can see sleet piling up on the backs of the birds), but Kim got her pictures.

Thinking about the extraordinary tameness of these birds, it occurred to me that they might not have had any prior experience of humans as something to be feared. They had come from a vast northern wilderness, and if they had come straight from the Arctic to this wild stretch of lakeshore, it was possible that we were the first humans they had ever seen.

Siskin Attack!

From Oak Harbor, Ohio, Kenn writes: I heard it this morning, high overhead, a sound that I'd been waiting for. Distant but unmistakable, a mix of querulous rising notes and dry rattles. Scanning the sky, I picked up a flock of half a dozen small, short-tailed birds, in high, bounding flight. Yes, they were Pine Siskins, all right.

Every fall, birders over much of the U.S. and Canada keep an ear toward the sky, listening for the calls of "winter finches" flying overhead. The "winter finches" are a group of about nine species that nest in the far north or in high mountains and that are mostly vegetarian in their diet: they eat seeds, buds, berries, but relatively few insects, unlike most other songbirds. These "winter finches" are extremely variable in their winter distribution. If there's a good supply of food in their nesting range -- a good cone crop on the spruces, for example, or lots of seeds on the birches -- the finches may stay in the Arctic all winter. But if wild food crops fail in the far north, the finches may invade far to the south. Depending on the season, other northerners may move as well: Bohemian Waxwings, Red-breasted Nuthatches, various northern owls. No two winters bring exactly the same mix of birds, and birders living south of the boreal forest always wait with anticipation to see which of these winter invaders will make an appearance.

Pine Siskin is a member in good standing in the "winter finch" group. A few siskins come south every fall, but some years there are huge numbers of them. It looks like this might turn out to be such a year. Just within the last few days, we've had reports of Pine Siskins suddenly showing up all over southern Ontario, southern Michigan, northern Ohio. These birds over Oak Harbor this morning may be part of a major flight. We should know for sure within the next few weeks.

That Time of Year

From Oak Harbor, Ohio, Kenn writes: For several years now I've been very interested in the whole subject of molt. This is the process wherein birds develop a new coat of feathers, generally by dropping a few feathers at a time, with new feathers growing in their place. Birders may not notice the molt unless they look closely, but it's a universal phenomenon among birds. Especially among smaller birds, it's generally true that a healthy wild bird will replace every one of its feathers at least once a year. Birders may not notice, though, unless the new feathers are strikingly different in color from the old ones.

The timing of the molt for most species is quite predictable. Right now, for example, here in northern Ohio, the American Goldfinches are starting their spring ("prealternate") molt. It's most noticeable on the adult males, who molt from very dull to very bright colors. This bird was outside the windows at the Black Swamp Bird Observatory yesterday, the last day of March. The occurrence of molt is one of the reasons why we have to look at the calendar when we're considering the identification of an unknown bird: it may be some familiar species in the process of going through a change.

People sometimes ask us why this bird is called the "American" Goldfinch, when it also occurs in Canada and locally in Mexico. Why not just "Common" Goldfinch, or "Yellow" Goldfinch, or something like that? Well, there's a good reason. Remember, I said that the bird shown above was just starting to molt. When it finishes the process of molting into its full summer plumage, usually around July 4, it will look like this:

As I said, we have to look at the calendar when we're considering an unknown bird; for some reason, April 1 produces more than its share of weird reports.

All seriousness aside (as the saying goes), the molt really IS going on right now, and it's affecting the appearance of many birds. The American Goldfinch is a great example to watch because it may come to feeders right outside your window and because the change of color on the males is so striking. But a high percentage of our small songbirds are going through some kind of molt of their head and body feathers at this season, and with a close study, you may be able to see the contrast between the crisp new feathers and the slightly older, worn, faded feathers. It's a part of the survival strategy of the birds and it's something we can witness for ourselves with just a little extra attention.