Science editor Gus Axelson recently posted about how the warblers of Europe don’t exactly measure up to our spectacular American warblers. That got the attention of Wesley Hochachka, assistant director of our Bird Population Studies program. Wes is an avid birder and has spent plenty of time in the field in both North America and Europe. He’s even visited Hortobágy, the Hungarian town whose warblers prompted Gus’s post. After careful consideration, Wes, who is Canadian, decided it was up to him to argue the case for European warblers. Here goes:
Just to be clear, I don’t have anything against American warblers (which are also called parulids, since they’re in the family Parulidae). I’ve even enjoyed summers doing field research with them, learning among other things that Virginia’s Warblers are the world’s most paranoid parents, while Red-faced Warblers are cute but not that bright. And I’ve spent enough time in Europe to have become familiar with most of their warblers.
I’ll admit that European warblers are not the most photogenic of birds. But if you look more than feather-deep, I maintain that in many ways they’re more interesting than American warblers. Here are seven reasons why:
Know thyself: European warblers may confuse us by looking the same, but at least they aren’t confused themselves. Multiple species live in the same area without mixing up which species is which. Compare that with North American warblers which, in spite of all that flashy plumage, seem unable to tell themselves apart consistently. Can a Blackpoll Warbler really be so oblivious that it can’t tell it has mated with a Northern Waterthrush? Seriously? And that’s just one of a long line of strange parulid hybrids that have turned up over the years.
Textbook species: Once you get to know the European warblers well, you could literally write a whole textbook on evolutionary biology, community ecology, and evolutionary ecology talking about them alone. And I do mean literally—that book was published a few months ago, and it covers this wide range of topics using just a subset of the Old World warblers: The Reed Warblers: Diversity in a Uniform Bird Family.
Delectable difficulty: I think European warblers demand (and reward) the close attention of birders, who must consider slight habitat differences, subtle variations in vocalizations, slight behavioral cues, and minimal differences in hues of legs and plumage. What’s the greatest challenge with identifying most breeding-plumage parulids? That’s little more than orienting yourself in the correct direction and opening your eyes.
Location, location, location: North Americans aren’t immune to the joys of difficult identifications—but lacking European warblers to challenge them, they are forced to turn to gulls. (Many gulls, I personally think, don’t even believe in the species concept, let alone abide by it.), This leads to American birders clambering around in garbage dumps to satisfy their ID-lust. In Europe, birders can do all this in the civility of a nice shady copse or garden. Personally, I’d say that European warblers are a birder’s bird.
Researchers’ muses: European warblers have made their mark in ornithology in ways American parulids never have. Was a deeper and clearer understanding of the ecological constraints leading to cooperative breeding the result of studies of parulids? No, this came from the Old World Seychelles Warbler. Did we learn that migratory navigation is genetically hard-wired from studying parulids? No again—that claim to fame goes to Blackcaps in Germany. What have we learned about the evolution of obligate brood parasitism from parulids and cowbirds? Not a whole lot relative to the elegant work on Common Cuckoos parasitizing Eurasian Reed-warblers and other species. What about mind-bending, species-blurring concepts like ring species (a sort of game of telephone played with genes)? Was this discovered with parulids? Nope, much of the foundational work was done on Old World warblers.
Trailblazing adventurers: Old World warblers have even colonized the New World—the Arctic Warbler breeds from Scandinavia across Russia and into Alaska. (In an extra show of chops, these Alaskan birds migrate back from the Western Hemisphere to southeast Asia each winter.) And then there’s the Wrentit: an Old World warbler that lives exclusively in the New World. It’s been hanging out in coastal California and Oregon for… oh, only about the last several million years. In contrast, parulids have yet to establish any breeding populations outside of the Americas.
Stamina: How long is a parulid’s song? Maybe five seconds. And they keep repeating the same song they learned from dad (and various neighbouring males) all their lives. Compare that to the Eurasian River Warbler of central Europe. It sings a single song—not a series of songs, but one continuous vocalization—for periods of time that you can measure in the tens of minutes [listen]. For versatility there’s the Marsh Warbler, which intermixes its own notes with imitations of dozens of African and European species [listen].
Basically, what I’m saying is that Old World warblers—with their subtle background hues, abstinence from garish markings, and all—deserve a lot more respect than that for which a North American bird watcher might give them credit. Anybody want to catch the warblers in Europe next spring? The opportunity to sample Europe’s diverse cuisines, old cultures, and millennia worth of historical sites… those would just be distractions from the birds.
(If you focus on more than just color, Wes argues, European warblers have a lot going for them. Images via Birdshare: European warblers at left: Arctic Warbler by Bill Thompson; Common Chiffchaff by Etienne Littlefair; North American warblers at right: Blackburnian Warbler by Danny Bales; Prothonotary Warbler by A wing and a prayer.)