Ornithologi

A studio for bird study

Tag: ecology

Dark-eyed Junco Subspecies in Idaho’s Winter

by Bryce W. Robinson

Juncos_ID-online-01.jpg

For the Junco lovers that like this image, you can purchase a print by clicking on the image above.

Above is an illustration I just completed of some select subspecies of one of my favorite birds, the Dark-eyed Junco (Junco hyemalis) – Male and female “Oregon” (J. h. oreganus), “Pink-sided” (J. h. mearnsi), “Cassiar” (J. h. cismontanus), and the nominate “Slate-colored” (J. h. hyemalis). I think the junco is a favorite because it is polytypic, with some excellent variation in phenotypes throughout its range. I particularly am drawn to the Cassiar Junco because it is both difficult to diagnose (separate from Slate-colored X Oregon intergrades, if they even are different!) and little understood. For more information on this taxon, check out these links:

http://ebird.org/content/nw/news/dark-eyed-junco-races-oregon-slate-colored-and-cassiar/

http://nwbackyardbirder.blogspot.com/2011/04/not-slate-colored-junco-cassiar-junco.html

Here is information on its current and past taxonomic status:

https://avibase.bsc-eoc.org/species.jsp?avibaseid=DED1C8F9EE711FCF

I also like the Dark-eyed Junco because from what we understand regarding it’s phylogenetics, it is a very recent radiation. Speciation well in process! See this article for an explanation:

http://digital.csic.es/bitstream/10261/157693/5/POSTPRINT%20Mol%20Ecol%2025(24)%206175-6195%20(2016).pdf

Further, be sure to educate yourself with the Junco Projects great film – Ordinary Extraordinary Junco. I included a chapter of the film below that discusses the diversification of the species.

 

My illustration comprises the candidate subspecies that make up Junco flocks here in western Idaho. I chose to illustrate the male and female Oregon because they are by far the most common and provide the point with which to contrast and compare any outliers. The others are males, so as to provide simple examples of the other subspecies. Of course first-year and female types of these taxa can blend in appearance with the rest, which makes things much more challenging and fun.

Here I’ve included a rough and disorganized compilation of some information on what we currently understand about the Dark-eyed Junco and its sister species. There is a lot more out there, so if you love this as much as I do then be sure to explore more.

Here is a link and a few  references to investigate.

https://borjamila.com/speciation-mechanisms-junco-radiation/

Milá, B., P. Aleixandre, S. Alvarez-Nordström and John McCormack. 2016. More than meets the eye: lineage diversity and evolutionary history of dark-eyed and yellow-eyed juncos. In Snowbird: Integrative biology and evolutionary diversity in the junco. Ellen D. Ketterson and Jonathan W. Atwell (Eds.), Chicago University Press, Chicago.

Miller, A. H. 1942. Speciation in the Avian Genus Junco. The American Naturalist 76:211-214

Advertisements

Mixed Woodpecker Flocks in an Alaskan Burn

by Bryce W. Robinson

2L3A9410

Male Black-backed Woodpecker working his way through a burn near Willow, Alaska. 

My friends Luke, Charlie, Linnaea and I recently visited a year old burn site near Willow, Alaska. Our purpose for the visit was to find a rarely encountered woodpecker species, the Black-backed Woodpecker (Picoides arctics). Luke had visited the site a year prior, only about a month after the burn, and found quite a few woodpeckers already foraging on the burned spruce. We were hoping to have the same luck.

When we reached the burn, we took a few roads that led towards the location Luke had luck in the year prior. While driving I noticed tan bark chippings flecked off of the charred trees, a sure sign of foraging woodpeckers.

2L3A9457

Downy Woodpecker foraging on a burnt spruce.

We set out on foot down a two track that led into a portion of the forest. Only two hundred meters down the track we heard woodpeckers. We first heard a Hairy Woodpecker (Leuconotopicus villosus), but soon after came the husky call of a Black-backed. We quickly had visual, and soon after had others. Multiple Black-backed Woodpeckers, the magic of the burn.

The flock foraged along through the forest, much like a winter passerine flock foraging through deciduous groves. Soon the birds had gone, and we continued down the track only to find more woodpeckers.

2L3A9447.jpg

Hairy Woodpecker foraging low on a burnt spruce.

We counted many individuals. At one point we were surrounded by Downy Woodpeckers (Picoides pubescens). Other birds joined the flock, including White-crowned Sparrow (Zonotrichia leucophrys), Ruby-crowned Kinglet (Regulus calendula), Myrtle’s Warbler (Setophaga coronata coronata), and Wilson’s Warbler (Cardellina pusilla). It was interesting to watch the woodpeckers interact with the passerines. Many times the Myrtle’s Warblers would chase the Downy and Hairy Woodpeckers.

Mixed flocks are excellent. Even more, a mixed flock is a symbol of fire ecology and the importance of natural fire cycles for many species, particularly Black-backed Woodpecker. Unfortunately I wasn’t able to get the photos I really wanted of the birds and their foraging behaviors. I’ll make it back to the burn soon, hopefully to film some behaviors as well. That way I can fully portray the importance of burns for these birds, and the excellent behavior of flecking bark in search of food.