Living the Scientific Life (Scientist, Interrupted)

tags: Junkin's warbler, birds, ornithology, DNA technology

With all the skilled birders and ornithologists in North America, it is truly remarkable to find a bird that cannot be identified, especially when that bird was captured in a mist net. After all, when you have a bird in your hand, you have the opportunity to examine its field marks closely.

Enter Dave Junkin. Junkin was the director of Buffalo Audubon's Beaver Meadow Wildlife Sanctuary in Java, and even after his retirement, he is an expert bird bander in western New York State. Because of his lifetime of bird watching and bird banding experience, Junkin has an intimate knowledge of North American bird species and how to identify them. But one day, he removed a bird from his mist nets that even he couldn't identify. He took a variety of measurements and his wife, Sandy, photographed the bird from several angles. Junkin then consulted his field guides and reference books, but to no avail. He simply couldn't identify his mystery bird.

Finally, he posted Sandy's pictures on the Web and asked expert birders for help. He received many guesses, but his question remained unanswered. As a result of this flurry of attention, the bird was christened with its own special name, Junkin's warbler.

Quite serendipitously, Junkin recaptured the bird one more time and, before releasing it this second time, he removed a single feather that he sent to Cornell University for DNA testing.

After the feather arrived, Cornell lab scientist, Amanda Talaba, removed the DNA from the feather and purified it. She then used polymerase chain reaction (PCR) to make billions of copies from very specific regions in the DNA, which were then sequenced. This DNA sequence data, which is a portion of the bird's genetic code, was checked against the lab's database library containing DNA sequnce data from more than 100 of the world's wood-warbler species.

Identifying the species of the mystery bird's mother was relatively straightforward because the mother, and only the mother, provides her offspring with all their mitochondria, and mitochondria carry their own separate DNA. After comparing the mystery bird's mitochondrial DNA sequence data to those in the database library, it was determined that the bird's mother was a Kentucky warbler, a species that is quite rare in the area.

Identifying the father was a bit more complicated. To do this, it was necessary to sequence a portion of the mystery bird's chromosomal DNA. This DNA, half of which is contributed by the father and the other half by the mother, is found in a cell's nucleus, so it is referred to as "nuclear DNA". The nuclear DNA sequence information were consistent with both Kentucky warbler and mourning warbler DNA. As a result, the ornithologists concluded that the father was a mourning warbler -- a more common species in the area.

So thanks to DNA technology, the mystery was solved. The mysterious Junkin's warbler is a hybrid mourning-Kentucky warbler, which is the first time that a hybrid has ever been recorded between these two species.

Cited story.