Wednesday, January 30, 2019

#Post 151: Introduced birds and vagrants: To count or not?

Some silly and mostly ridiculous thought from the bike the other day.....

I see the introduced European Starling on just about every Bay Area birding outing. The species is so widespread and abundant I think of it as a native species. I count it on my ABA list and my Bay Area bike list - the only two lists I care about. I eBird starling without hesitation.

In contrast, I see the introduced Red-masked Parakeet on some of my San Francisco birding outings. I know the species is introduced and treat it differently than native species. It is not on any of my lists, and I don't even bother to eBird it since I don't want it 'contaminating' my species totals (and yes, I realize I'm selectively skewing the data by doing that. But who cares, its Red-Masked Parakeet).


The introduced European Starling

Both the starling and the parakeet are introduced, so why do I consciously draw a distinction between them for listing purposes? It is because the starling is so comparatively widespread? Is it because the ABA deems the starling a countable species? It is because there is some unspoken agreement among birders letting us treat the starling one way and the parakeet another?

I don't know the answers to these questions, but I do know some ultra-pure listers ignore all introduced species, presumably to avoid drawing the sorts of arbitrary designations I've highlighted above. Those strictest listers will often quote their various lists with the caveat 'NIB' - non-introduced birds - attached. Though I don't adhere to this convention, I understand it and think it makes general sense.


The introduced Rock Dove

Or does it? All of the introduced species I've mentioned in this article are infinitely more a part of the North American avifauna than, say, the continuing Red-flanked Bluetail in Los Angeles. From an ecological or demographic standpoint, the Bluetail is irrelevant; it's nothing more than a statistical anomaly. If we're so concerned about birds that are naturally North American, then the Bluetail should be the last bird on our collective mind, right?

I obviously ask this question rhetorically; if I could have biked to the Bluetail, I would have been the first one in line to see it. I suspect most folks feel vagrants arrive via their own - albeit disoriented - volition while introduced species have been translocated and aided by humans. That also makes sense, but how should we consider climate change moving forward? If we agree it's mostly human caused (and if we don't, then please never talk to me again), then any vagrancy or population shift influenced by climate change would be unnatural, right? It would be as impossible to prove that any rarity didn't wander because of climate change as it would to prove that a foreign vagrant didn't ride a boat or ship to our shores (and I realize trying to prove a negative is futile anyway).


On a boat....
(Thanks to Paul Reinstein for the Bluetail photo!)

I present these musings mostly to elicit opinions/comments from those of you who haven't fallen asleep by this point. I'm as certain as anyone the Bluetail is a natural vagrant, but I think our treatment of 'natural' might need to shift moving forward. The same for introduced birds that outstrip native species. Birds like Whooping Crane and California Condor present other sorts of intrigue; humans rescued those species from human-created population crashes. Should that mean anything for countability? Listing is fun but the whole process can feel like a black box. I particularly feel for folks on records committees; trying to sort out what should count and what shouldn't seems like trying to run the 100-yard dash in a 90-yard gym. Photography sometimes seems so much simpler. Here's a native bird to close, later.....


Dunlin - Calidris alpina
San Mateo County, California
Canon 600mm f/4 IS II on EOS 1DX Mark II
1/5000 at f/4, ISO 400, handheld

2 comments:

  1. Fun post about a conundrum most serious birders have struggled with. Btw, the common wisdom I've always heard is that Cattle Egrets are in fact natural colonizers of the New World. The Wikipedia article supports this. I've always been intrigued by that postulate.

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  2. Interesting about the Cattle Egret - Guess I'm guilty of not doing enough research! Thankfully doesn't change the message of the post, silly as it is! Cheers, glad it entertained you regardless......

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