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Who's Kenn? Simply put, Kenn is a national treasure. A renowned birder, author, and conservationist, Kenn Kaufman has spent his life dedicated to observing birds, reading about birds, writing about birds, and sharing the world of birds with others. With all that birdy knowledge in his brain, he also acts as the field editor for ���Ϲ��� magazine. So, whenever we have a bird question stumping us around the office, we just ask Kenn. And now you can, too! If you have a bird or birding question you'd like Kenn to answer, leave them in the comments below or on Facebook. Maybe next month you'll get the kind of thorough, thoughtful, and even humorous response from Kenn we've grown so fond of over the years. —The Editors 

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Q: With Valentine's Day coming up, I was wondering about those little parrots called lovebirds. Why are they named that? Are they really more affectionate than other birds? 

KK: Parrots in general have strong, long-lasting pair bonds, and many species are known to mate for life. But in the nine species of lovebirds (genus Agapornis), native to Africa and Madagascar, those romantic bonds seem unusually close and intense. 

These are small, short-tailed parrots, a little smaller than an American Robin, with mostly green bodies and patterned heads. They reproduce well in captivity and are popular as cagebirds, so they’re familiar to many people around the world who would never have a chance to see them in the wild. And anyone who has paid attention to a pair of lovebirds can’t help but notice their strong attachment to each other. 

In many species of parrots, as in various other kinds of birds, it’s common for the male to feed the female as a part of courtship. Lovebirds take this to the next level. They feed each other during all seasons, especially after they’ve been separated or subjected to some other kind of stress. When one bird is passing food to the other, beak to beak, it looks for all the world as if they were kissing. Members of a pair also regularly spend time preening or grooming each other’s feathers; when at rest, they often perch very close together. And because they’re small and cute, it’s hard to avoid the sense that they’re “cuddling” or “snuggling.” Lovebirds indeed!

When the genus Agapornis was first named—in The Natural History of Parrots, published in 1836—the author, Prideaux J. Selby, didn’t discuss the behavior of the birds, but clearly he was aware of their seemingly affectionate nature. The name itself reflects it: agape (ἀγάπη) from Ancient Greek for love, plus ornis (ὄρνις) for bird. The English name “love-bird” was already in use for these little parrots at that time, so the scientific name may have been simply a translation of that term.    

In Spanish, lovebirds are called “inseparables;” in French, “inséparables.” The words mean just what you think they mean, and they’re a perfect reflection of the way these birds seem utterly devoted to their mates. It’s hard to imagine more fitting birds to celebrate on Valentine’s Day.

Q: How many bird species are technically in the United States? Or in the world? I've seen different numbers, and there doesn't appear to be a straight answer.

KK: Those should be straightforward questions, right? But in fact, it’s impossible to give precise answers to them. And there are some fascinating reasons why that’s true.

How many bird species are there worldwide? To start to answer that, we have to back up and ask: What is a species? There’s no simple answer. Many definitions have been proposed, and several are in use right now. Even among scientists who define species the same way, though, there are differences of opinion in how to apply the definitions in particular cases.

Many examples exist here in North America. A committee of the American Ornithological Society (formerly American Ornithologists’ Union) decides the “official” classification used at any given time, but committee decisions often are not unanimous; opinions vary, and they change over time. Baltimore Oriole and Bullock’s Oriole were lumped into one species, called Northern Oriole, in 1973 (because they hybridized a lot), then split again in 1995 (because more fieldwork showed that they didn’t hybridize that much). Thayer’s Gull and Iceland Gull, long treated as two separate species, were lumped into one in 2017, but some experts question that move. For such close relatives, even genetic analysis may not provide a complete answer. Scientists have debated for decades whether the Common Redpoll and Hoary Redpoll are separate species; even though they seem to be genetically almost identical, the AOS committee still has found reason to keep them separate for the time being.   

These examples are from North America, where the birdlife is relatively well-studied. Mysteries abound in tropical regions where studies are not so far along. Many tropical forest species may look almost identical, differing mainly in voice, but it takes careful field research to work out these distinctions. As a result, new cryptic species are being detected every year, and many open questions surround borderline cases of birds that may or may not be distinct.

As a final complication, no single scientific body is recognized as a source for decisions about which birds are full species worldwide. In North America, ornithologists and birders go along with the classification published by the committee of the American Ornithological Society, even if they may privately disagree. But globally there’s no group with the authority of the AOS, so there are several different lists of birds of the world, and they all have different totals because of different decisions about which species to split or lump. So if we want a precise number we have to pick just one source, and acknowledge that it represents just one set of opinions, not established fact.

Okay, but if the AOS is the authority here in North America, we should be able to accept their number for how many bird species are in the United States, right?

Yes, that’s sort of true, but we still need to qualify the answer. The total number of bird species ever recorded in the United States is now over 1,100, but that includes more than three dozen species that are now extinct, mostly in Hawaii. Do we count the extinct birds? And what about the many extreme rarities that have shown up only once or twice and may never be seen in the country again? For example, a Rufous-necked Wood-Rail was observed in New Mexico in 2013. This sedentary, tropical marsh bird was not on anyone’s list of expected species, and it may never appear again north of the border. Should it count as a bird that is “in” the United States?

In avian terms, we could say how many bird species have ever been found in the United States, including extinct and accidental species, and that number would gradually go up over time. Or we could say how many species occur here regularly. But the latter would be an approximate number, because there are so many borderline cases, depending on how we define “regularly.” Do we count only those species that appear reliably every year? Do we count rare-but-regular birds that show up several times per decade but not every year, like White-throated Thrush? Where do we draw the line?  

It’s because of questions like these that I always encourage my friends to avoid false precision. How many bird species exist in the world? Oh, probably between 10,500 and 13,000. How many have been recorded in the United States? More than 1,100. How many occur in the U.S. regularly? Somewhere between 800 and 1,000. These are vague numbers but they’re accurate, more accurate than any precise figure could be, and I think we should learn to be comfortable with such approximations.

Q: Some birders I know found three different rare birds in a local park. Someone said it was an example of the "Patagonia Picnic Table Effect." The park doesn’t even have a picnic table. What were they talking about?  

KK: Ah, the PPTE. A useful term to know, and it reflects a fascinating chapter in birding history.

In southern Arizona, Highway 82 runs alongside Sonoita Creek for a few miles. Southwest of the town of Patagonia there’s a roadside rest stop, with a few concrete picnic tables in the shade of big cottonwoods and sycamores. The rest stop has long been a popular birding site, and it became more so in the 1960s, when a local schoolteacher and birder named Bill Harrison started to make some interesting finds there.

Harrison began to visit frequently because Rose-throated Becards, rare north of the Mexican border, were nesting there, and in 1961 he found Thick-billed Kingbirds nesting there as well—only their second colony in the United States. This was reason enough for Harrison and other birders to keep going back, and they kept making discoveries: a nesting colony of Five-striped Sparrows, previously known from just one Arizona record. A Yellow-green Vireo. A Yellow Grosbeak. The first Black-capped Gnatcatchers for the United States. And on and on, with more exciting finds.

What made the roadside rest so special? It has good habitat, but not exceptionally so. All the rare birds I’ve mentioned have since been found at numerous other spots around southern Arizona. They were found first at this single, specific location because that’s where the birders were concentrating their efforts. Every time a rarity was found, the roadside rest stop became more of a must-visit for birders; and with so much coverage, they kept on finding more rare birds. It’s a type of feedback loop that plays out repeatedly in birding.

An example on the opposite side of the country occurred in 1971. At the Brigantine National Wildlife Refuge (now the Brigantine Unit of the Edwin B. Forsythe refuge), John Yrizzary discovered a Black-tailed Godwit on May 22nd. This big Eurasian sandpiper is a rare visitor anywhere in North America, so as it stayed into summer, birders came from all over the eastern states to see it. Visiting Brigantine on June 28, John Danzenbaker found a Bar-tailed Godwit, almost as unusual as the Black-tailed in the east. The presence of these two rare godwits at once (with both staying until late August) was enough to lure even more birders, and they continued to find more rarities. The two North American species of godwits, Marbled and Hudsonian, were both found during the summer—on dates when neither would have been expected in New Jersey—giving some birders the unique experience of seeing all four of the world’s godwit species on the same day. Curlew Sandpipers, Ruffs, Wilson’s Phalaropes, and other rare birds all added to the summer’s excitement.

Brigantine has fine habitat, but it’s not unique. All of those rare shorebirds could occur (and have occurred) at other points along the coast. But that year, because of the Black-tailed Godwit found in May, birders were scouring the area every day, turning up more and more finds.

At the time, several people made the point that this was the same kind of feedback loop that had developed at the roadside rest in Arizona. But I believe it was ace birder P. William Smith who coined the term “Patagonia Picnic Table Effect.” It had such a great ring to it that birders have been using it ever since—even in places where there’s not a picnic table in sight.  

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Have a bird or birding question for Kenn? Leave it in the comments below, and maybe he'll answer it in a future column.