Eastern Bluebird (1 Viewer)

Avery, Fonseca, Campagne & Lockwood (in press). Cryptic introductions and the interpretation of island biodiversity. Mol Ecol. [abstract] [supp info]

Collar 2005 (HBW 10).

Gowaty & Plissner 1998 (BNA Online):

S. s. bermudensis Verrill, 1901: Resident in Bermuda. Said to be darker and deeper red below; males brighter (not purplish) blue above. Considered a synonym under nominate sialis by some.

Click to expand...

Avery et al 2013. Mol Ecol 22(8): 2313–2324.

• Hannah Waters, Scientific American, 8 Apr 2013: Bermuda Bluebirds Aren’t Native: They Moved In 400 Years Ago.
  
  
• Birdwatch, 13 Apr 2013: Bermuda triangle for bluebirds.

The successful colonization of an island by a species that got there on its own makes it a native species -- Eastern Bluebird should be deemed a native species on the island. All native birds on islands such as Bermuda originated from successful colonization events... what a strange article by Hannah Waters.

Carlos

I had a bit of the same feeling of unease that Carlos expresses after reading the Waters blog. The low variation within the population in principle can mean one out of two things: either a severe bottleneck recently or a longer period with a very low population size -- and if the bottleneck only lasted a short time it would have to be very severe indeed.

Likewise, I am curious how "two unique genes across all the Bermudan bluebirds" (whatever that expression really covers) is shown to be more congruent with 400 than with 1000 or even several thousand years?

Niels

csanchez7 said:

The successful colonization of an island by a species that got there on its own makes it a native species -- Eastern Bluebird should be deemed a native species on the island.

Click to expand...

Well, if colonisation truly occurred only ~400 years ago, then it's highly likely that it occurred as a result of direct or indirect human action.

But I don't know what date in history (presumably several thousand years ago?) is usually accepted as a cut-off between 'natural' and modern-human-influenced colonisation...

Richard Klim said:

Well, if colonisation truly occurred only ~400 years ago, then it's highly likely that it occurred as a result of direct or indirect human action.

But I don't know what date in history (presumably several thousand years ago?) is usually accepted as a cut-off between 'natural' and modern-human-influenced colonisation...

Click to expand...

If Wiki is correct, the Clovis culture in North America has been dated to between 11000 and 13500 years ago. Bluebirds in the US may therefore have been influenced by humans for about that period of time. However, Bermuda seems not to have been influenced by humans before Europeans discovered it.

Niels

Having visited Bermuda in March, intrigued by the inference in the report. A lot of effort is put in by Audubon Bermuda/Bermuda Bluebird Society (and members of the local population) to support the Eastern Bluebird through the creation of nesting boxes/sites and the discouragement/eradication of invasive (my emphasis, although Audubon's word) house sparrows and starlings (some Parks Dept members are licensed to shoot them) and the Kiskadee. Unfortunately, their own (Audubon's) sponsored study seems to blow a bit of a hole in such a conservation programme....eradicate one 'invasive' species to support another?....or am I reading this wrong? The Bluebird turned up in Bermuda because man brought it over (and released it/escaped....a la ring necked parakeet in Europe) or the occasional migrating bird(s) found a landscape (because of clearance) more to their liking and could thus develop a viable population......? The former creates a conservation dilemma, the latter requires a seemingly significant number of coincidences to occur (and I did try to follow the article's online 'supp info' but I'm afraid it beat me!). Seems a shame as a lot of effort (and not a little national pride) is put into supporting a 'native' species which it may not now be.

Bermuda (continued)

Avery, Cassey & Lockwood (in press). Contemporary divergence of island bird plumage. J Avian Biol. [abstract]

To be fair, different plumage might be better explained by founder effect not evolution (that is, original few colonizers were especially colorful).

BTW, house sparrows in North America are also said to evolve plumage differences per Sibley (being paler in desert regions etc). Anybody knows how visible it is?

jurek said:

BTW, house sparrows in North America are also said to evolve plumage differences per Sibley (being paler in desert regions etc).

Click to expand...

Also mentioned in this thread: House Sparrow Releases.

jurek said:

To be fair, different plumage might be better explained by founder effect not evolution (that is, original few colonizers were especially colorful).

Click to expand...

I haven't read the paper so I don't know what they argue, but a founder effect is evolution. It's not natural selection, but it is evolution.

I think that differences between house finch released on the east coast and birds from their original range has been noted

Niels