Late Warbler Species Still Arriving? Answer: Possibly "Yes"

Tardy me, I’ve been enraptured in my Wisconsin wood-warbler tour (at the Festival of Nature in n. WI) and watching the Prime Time Migration in my home state (WI).

Thus, I’m just back and now digitally-efficient again (vs. digitally deficient in the WI northwoods where I visited).

I’m no ticker, but I do count high enough to note that I detected 25 species of wood-warblers…..without being in “chase” mode. Lots of fun mornings (and days) carousing for the spring birds. It was a 24/7 birding foray. As such, Doc, would you say I have the malady of ASD (Attention Surplus Disorder) for wood-warblers? (They’re my second favorite family…….next to my own).

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Enough of me, TODAY’S TOPIC relates to the “phenology”/seasonal dates for LATE-ARRIVING wood-warbler species in the Upper Midwest.

This question was posed to me on my tour that I led for the “Festival of Nature” (www.ridgessanctuary.org) (below entry from 5/13/08) as:

“Which wood-warblers are the latest ones to arrive on migration (in the Midwest)?” (asked by Kate Aaron, 5/22/08)

My answer follows#, below:

(# = i.e., spring migration arrival of wood-warblers is, in general, a factor related to wind patterns/weather/temperature, in addition to the level of insect bloom resources present on the landscape. It’s an inexact science, to be glib. BUT tracking the Gulf Stream wind patterns (south and southwest winds are ideal) are good indicators as well as storms/fronts that SOMETIMES serve as harbingers that large numbers of neotropical species/wood-warblers will, in turn, premiere on the landscape.)

Given I grew up in Wisconsin, the following brief, oversimplified information is most pertinent to the southern Wisconsin region, though it’s also generally true for the Upper Midwest region as a whole:

1. Blackpolls and Connecticut Warbler are considered two of the last flavors to arrive on the landscape, though their premiere date may vary widely from spring to spring in s. WI/Upper Midwest.

2. For example:
During some springs (such as this one), Blackpolls may arrive in early May*.

To wit:

This spring, I heard Blackpoll on the first day that I arrived (5/14/08*) while the initial flavors – Yellow-Rumped (YRWA) and Palm Warbler (PAWA) -- in the vanguard march north were ALSO present in large numbers.

(* = Blackpoll may arrive even earlier (late April-5/10 in s. WI is not uncommon)

3. In turn, encountering this kind of species mix is anomalous in my experience of watching the spring march of neotropical migrants in Wisconsin during the last 30 years. (I visit in May and in September, ostensibly to monitor the wood-warbler spring and autumn migration.) The spring weather this season was so cool that I surmised my initial 5/14 birding foray felt more like 5/1-5/4 – in terms of the avifauna species diversity present.

4. That is to say, during most spring seasons, I’ll see Blackpoll AFTER all of the YRWA and PAWA are gone from the landscape – given they do NOT nest in s. WI. Neither does Blackpoll, of course, but it’s typical arrival during some spring seasons is later than the majority of the other newly-arriving migrating wood-warbler species.

In fact, it’s not too unusual for Blackpoll (and Canada, Mourning and Connecticut as the best examples) to arrive in late May and/or, even, early June (though Blackpoll would be the best candidate for a June seasonal premiere in s. WI.

5. A good source for the phenology/seasonal arrival of wood-warblers on the landscape in s. WI/Upper Midwest is "Wisconsin Birds: A checklist with migration graphs" (6th edition, Stanley A. Temple, Robert C. Domagalski, John R. Cary, WI Society for Ornithology, 2003)

6. Lastly, as a personal anecdote, I’ve been in Upper Michigan in the second and third week of May. At this time, along Lake Superior, I’ve met birders searching for Connecticut Warbler in nearby counties. I’m often too sheepish to spoil their fun pursuit, as this species is typically NOT yet present.
Thus, my final tip today is to tell the Yooper/UP’er (Upper Michigan) bird-sleuths to consider the possibility that better Connecticut Warbler (prize-)viewing success may happen by the fourth week in May and, even, early June.

Good (wood-warbler) birding to all…..Daniel