Wednesday, January 22, 2014

Banding results part 2: more old and confused birds


Bird banding in PNG Part 2.  "Old and confused" birds

The longevity of the Chaetorhynchus "drongo" was not that unusual.  Quite a few other species had individuals living over a decade.   The list of species living long is basically just a list of the most commonly caught species-- indicating that with enough captures we'd find lifespans over a decade is probably the norm for most species.

Size doesn't matter.  At 11 years and four months, the miniscule Gray-green Scrub-wren (Sericornis arfakianus) was the third longest-lived recapture.  The mean weight of these guys was 9.2 grams, just over a quarter of an ounce-- less than the weight of two quarters.  The nearly as small Dwarf Honeyeater (Oedistoma iliolophus) weighing in at about two quarters and a penny had the second longest recapture interval-- 11 years and six months.

Like the aforementioned "drongo" that isn't really a drongo, the Dwarf Honeyeater turns out not to be a honeyeater upon examining its DNA.   Ditto for the Long-billed Honeyeater (Toxorhamphus poliopterus): oldest 10 years 9 months.  This is the state of knowledge of birds in New Guinea.  Many species are categorized based on superficial characters that are highly variable and subject to convergence.  These "honeyeaters" have a thin decurved bill like many other honeyeaters, a diverse family centered in Australia-New Guinea.  But look at the DNA and they come out closer to the Berrypeckers.  Anything that feeds on nectar might evolve a thin decurved bill, that doesn't make them related.  Honeyeaters are not related to our nectar-feeding hummingbirds or sunbirds of the Old World.

The Black Berrypecker (Melanocharis nigra) is another common bird at the station, captured 436 times.  The longest-lived was just over 11 years between captures.  These birds have been a bit challenging to ornithologists also.  They've been aligned with several different families depending on the predispositions of ornithologists.  But few ever lumped the berrypeckers, with their short stout-ish bills, with the faux honeyeaters Oedistoma and Toxorhamphus with their long, thin bills.  (Can you see why I like the Latin names better than English Names?  You can place Oedistoma in any family, but when you say a honeyeater is a berrypecker, it gets confusing.)  Now it is beginning to look like Berrypeckers (Melanocharis), and the "honeyeaters" Oedistoma and Toxorhamphus, are all related.  They might best be considered their own family, a family that is endemic to New Guinea, best called the Melanocharitidae.

Slaty-chinned Longbill (Toxorhamphus poliopterus).  The species most commonly banded at the Crater Station.  The oldest recaptured was at least 12 years old.  Superficially similar to honeyeaters and the spiderhunters of SE Asia.  It is neither, and appears to be part of a family unique to New Guinea.

If you are confused, good.  The ornithology of New Guinea is confusing and only a handful of workers are sorting it out.  I'm certainly no expert on the evolutionary relationships of New Guinea's birds.  I'm more of an ecologist and natural historian.  My research doesn't resolve who is related to whom, but I can give a little idea of how long some birds live and what they do in that lifespan.  I think it is exciting to think that a group of birds isolated in New Guinea radiated into different niches-- some eating fruits and evolving a stout bill and others becoming nectar and insect eaters and evolving thin decurved bills.  When I started out the banding project, I did not know I was collecting data on a family of birds endemic to New Guinea.  I'd hazard a guess that there are very few, if any, entire bird families in the world that ornithologists have studied less and know less about. 

Friday, January 10, 2014

Banding results part 1: the oldest bird


Bird banding in PNG part 1
The oldest bird

I did not spend all my time at Crater searching for pekpek.  For the sake of advancing science I started a bird banding (or what the Brits and Aussies call "ringing") program.  There was no permanent banding station anywhere in New Guinea, no long-term monitoring of any population of marked animals of any species.  Science screamed for a banding program.  Yeah, that's the reason.

Actually I started banding because it is fun.  You never knew what you would catch.  Each month I'd run a line of nets along a different trail.  I'd walk back and forth along the trail, banding and releasing as I went, never knowing what might be in the next net.  A few times I've been surprised with snakes or lizards.  Once a fish in the net 5 feet above the ground and hundreds of yards from the nearest water.  Once we caught a bird with a small frog in its beak that turned out to be an undescribed species (the frog, not the beak).

I've written an essay about banding published in "Tale Feathers" edited by Jackie Howard (http://www.celebratebirds.com).  It is available on for Kindle also.

After my first long residence at the station, I published a technical paper about the birds of Crater (co-authored with Debra Wright in 1996) in Emu (available under the Academic Research tab on this website).

That first paper told me we needed a lot more data before we could understand what was happening at Crater-- when birds breed, when they molt, etc.  So I engaged the help of many volunteers up until 2006 to band more birds, especially from Doug Schaeffer and Stephen Oppel, who each spent about a year at the station.  With the help of these people, we racked up thousands of captures.

I've begun compiling and analyzing those data for another publication.  I thought it would be fun to share some interesting tidbits here as I slog through the data in my spare time.


Oldest Bird

The longest interval between first capture and a recapture was 4402 days, or just over 12 years.  The bird was banded the first month we were banding (May 1992) and just six months from the end of the study period in June 2006.  What was it?  drum roll....

A Mountain Drongo, Chaetorhynchus papuensis.  Never heard of it?  Most people haven't.  It is an all black bird, weighing less than two ounces (40 grams), that lives in the forest understory of foothills to mid-montane forests of New Guinea (and no where else).  It catches insects and has a nice strong hooked bill to hold them (or the bander's fingers) and prominent hairs (rictal bristles) around the mouth.  Its Latin name Chaeto- for hairs, rhynchus- for bill, translates to something like the Papuan HairBill.  I'd go for a name like that (reminiscent of HairBall), but ornithologists have called it a Drongo, thinking it is allied with a group of mostly southeast Asian birds that are also black insect eaters.

Mountain Drongo, Chaetorhynchus papuensis, ready to be banded at the Crater Mountain Field Station..
Modern DNA analyses are suggesting Chaetorhynchus is not really related to Drongos.  The similarities in plumage and bill shape are likely just matters of convergence due to similar habits.  If ornithologists remove it from the Drongo Family, they'll have to come up with a new English name for it.  I'll lobby in favor of Papuan Hair-Bill, or New Guinea Hairy-billed Finger-Biter. 

Wherever it belongs in the evolutionary tree, I think it neat that a little bird like this lives so long.  If we had been able to keep the program going, we might have learned just how long they can live.  I'm guessing more than 20 years is possible.