Question: Flocks of Pied-billed Grebes?

This is just part of a flock of 97 Pied-billed Grebes seen at Metzger Marsh on September 21. The species is common here, but I haven't noticed this flocking behavior before. Photo by Kenn Kaufman.

September 21: Metzger Marsh Wildlife Area was loaded with Pied-billed Grebes during this nesting season, and I frequently saw and heard good numbers when I visited in May and June.  But today I was surprised to see a flock of Pied-billeds.  They were near the outer dike of the marsh, concentrated in one straggling string, and I carefully counted 97 individuals in this group.

I'm accustomed to seeing flocks of some other kinds of grebes.  Out in western North America, Eared Grebes regularly gather in large flocks on lakes, and Western and Clark's grebes will flock up on lakes or on coastal bays.  But with a marsh-dweller like the Pied-billed Grebe, I don't recall ever seeing such a concentration. 

It's possible that recent activity by anglers and hunters in the marsh has spooked the grebes out into this more open area of the impoundment, but I don't know that.  In addition to the flock of 97, I did see other scattered singles closer to the areas of dense vegetation, so at least some of the birds were acting the way I "expected" them to.

Insight: the blackbird divide

July 5:  This evening I happened to be outside at two different spots during the time that blackbirds were flying to roost.  Even though these two spots were not far apart, the birds were flying in completely different directions, revealing something of their behavior.  

In the town of Oak Harbor, I watched flock after flock of Red-winged Blackbirds, Common Grackles, and European Starlings flying over, all headed south or south-southeast.  It was near sunset, and these birds undoubtedly were all flying to a communal roosting site where they would spend the night: possibly in marshes or dense thickets along the Portage River on the south side of town.  

Leaving Oak Harbor, we drove to a farmhouse about three miles north of the town.  Flocks of blackbirds and starlings were flying over here as well - but here, they were all flying north, or north-northeast.  Clearly they were headed to a different communal roosting site than the birds seen just a few minutes earlier.  

At this time of year, it's normal for these birds to forage widely in the countryside during the day, and then fly to these communal roosts at night.  They may fly a considerable distance to a good roosting site.  But somewhere within the first three miles north of Oak Harbor, evidently, there was some kind of divide between birds going to two different roosts.  

Something that I don't know, to look into in the future: would these birds always go to the same roost every night, or might some individuals go to alternate sites on different nights?  

Insight: Birds don't read the weather maps

April 30: Last night, after carefully studying all the weather maps, I predicted that the next big flight of migrants would arrive in NW Ohio no earlier than May 2.  The weather last night didn't look favorable for migration here: winds were from the east, or even the northeast, with some rain in the latter part of the night.  But despite that, people who were out early this morning reported an excellent arrival of migrants, with numbers of Baltimore Orioles and Rose-breasted Grosbeaks, and a big increase in the variety of warblers present in the area. 

So why was the prediction so far off?  One possibility is that we're reaching the point in the spring at which birds will go ahead and move without waiting for ideal conditions.  Especially these mid-sized songbirds, like orioles, grosbeaks, Gray Catbirds, and Great Crested Flycatchers, all of which arrived in numbers today, may be able to migrate as long as they're not battling strong headwinds.  It's also quite possible that the winds above 1000 feet were different from what we experienced on the ground - those winds may have been southerly, like the prevailing winds in areas to the south of us last night.  Whatever the reason, today was a good reminder of the fact that we can't always predict what will happen with the migration.

Question: Yellow Warbler - arrivals vs transients

Yellow Warbler: As a general impression, the local males show up on their summer territories before we start to detect many at the migrant traps along the lake. Is this an illusion, or does it reflect the actual pattern of their migration? Photo by Kenn Kaufman.

April 26 (Audubon's birthday): Here in the region of the Lake Erie shoreline, the woodlots or "migrant traps" along the immediate lake shore have such a concentrating effect that we usually detect migrants there before we start to see them elsewhere in the vicinity.  An exception to this pattern involves Yellow Warbler, which is one of the few warblers to nest commonly in this area.  My impression from past years -- borne out by observations the last few days -- is that male Yellow Warblers show up on their nesting territories a mile or two south of the lake first.  Today they were singing vigorously in several spots south of the Magee boardwalk, such as near BSBO and the Sportsmen's Center, but the first migrants are just now showing up at the boardwalk itself.

Does this mean that the birds that are going to nest here arrive first, while the transients going farther north arrive later?  Or are the local summer resident birds just a lot more conspicuous because they are singing and setting up territories? 

Incidentally, something like this happens with Willow Flycatcher later in the spring.  In the latter part of May, they suddenly show up on their territories in the scrub-shrub habitat around BSBO, and only a few days later they start to become conspicuous in the migrant traps right on the lake shore.  But again, the singing, territorial males are a lot easier to detect than the transient individuals.

So for the moment I have a question without a solid answer.  I suspect that local breeders are among the very first Yellow Warblers to reach this latitude, but I don't know that for sure, and I'll have to look into it further.

Question: Differential timing, sparrow version

Fox Sparrow (eastern, or "Red," population):  We know it's an early migrant, and that makes sense, but we don't know why some sparrows are later.  Photo by Kenn Kaufman.

April 22: Thinking today about two species of sparrows and their migration through NW Ohio.  Numbers of White-throated Sparrows are just now starting to build up, while the peak of Fox Sparrow migration is already well past.  This timing is already well known.  But I'm wondering: why does it differ so much between these two species?

White-throated Sparrows and the eastern population of Fox Sparrows have similar ranges in summer and winter.  They nest in boreal forests across Canada and winter in the eastern United States. White-throated Sparrow has a broader range at both seasons, with its breeding range extending well south into the northeastern U.S.and its wintering range extending north to the Great Lakes.  (Look at any field guide that has range maps to see what I mean.)  Still, their overall distributions are similar.  Hence my question: why do the Fox Sparrows move north a full month earlier, on average, than the White-throated Sparrows? 

Insight: In before the door closes

Male Black-throated Green Warbler: a few arrived in the area within the last couple of days, just before the wind shifted back around to the north. Photo by Kenn Kaufman.

April 20th: We've just had a couple of days and nights of southerly and southwesterly winds, and this evening the wind shifted back around to the northwest.  It looks as if it will stay that way for at least a few days.  But as a result of this recent weather pattern, we have a decent variety of birds around in northwest Ohio. 

This most recent push brought in very large numbers of Yellow-rumped Warblers and White-throated Sparrows, and lesser numbers of other typically early migrants, but it also brought a handful of species more typical of the end of April and beginning of May.  Lakeshore migrant traps like Magee Marsh and like the Black Swamp Bird Observatory main banding station a little to the east reported a few individuals of many species of migrants -- I heard reports of at least 20 warbler species being found within the last couple of days. 

This is a good reflection of the importance of noting numbers of individuals.  If we just reported a species list, it would give a very misleading impression of what's going on.  For example, we might list Yellow-rumped, Black-throated Green, and Yellow warblers.  But if we note that we saw 100 Yellow-rumped Warblers, 3 Black-throated Green Warblers, and one Yellow Warbler, it gives a better idea of what is happening with the migration.

Question: Where are these Avocets going?

Three of seven American Avocets (hanging out with Ring-billed Gulls) at the inland beach at Maumee Bay State Park, Ohio, on April 15, 2012. Photo by Kenn Kaufman.

Mid-April:  Yesterday while Ethan Kistler and I were on the hawk tower at Magee, he got a call from Sherrie Duris, who was over at Maumee Bay -- looking at 7 American Avocets.  These snazzy relatives of the sandpipers are generally rare in Ohio, so we couldn't resist running over to the park to look at them.

It's quite possible to go through a year of birding in Ohio without seeing any avocets at all.  But when they're seen -- and especially when they're seen in spring, I think -- they often occur in flocks, not as singles. 

This is mainly a western species.  It can be abundant on the Pacific Coast and on wetlands in the interior of the west.  It may nest as far east as the Dakotas and western Minnesota, and fairly small numbers spend the winter as far east as Florida and South Carolina.  But when I draw a line from any point in the winter range to any point in the breeding range, Ohio is not along that line.  American Avocets that show up here are not taking the most direct route.  Are they just wind-drifted off course, in flocks, every spring?  Or is there something else going on?