Front Range Bushtits-What's Up Wtih That?
Doug Ward
“Long time Colorado birder, first time CoBirds poster”. After being away for 17 years, I find myself back in the Front Range of Colorado on a regular basis now. Being born and raised here, I had over 25 years of birding experience before heading north to Coeur d’Alene, Idaho in 2000; actually splitting time between Colorado & Idaho now. With family down here, we were back for holidays, but never really got out to do much birding – plus after 25 years, I had a pretty good idea of what, and how many, were where, or so I thought.
Ted’s post last night (25 Feb.’17), “magpies, flickers, bushtits, and Bill Kaempfer”, prompted me to write this note based on one of the significant avian changes I’ve noticed along the Front Range since being away. Last summer, my wife and I were working in the yard here in Denver (Denver, Co.) and I heard the distinctive “twittering”, then “Holy s&#$, BUSHTITS!!!” (she still thinks the AOU needs to change the common name of these guys; I for one like it as I’m a perpetual adolescent). I immediately ran to eBird to check recent occurrences as I was sure this was huge. Turns out, not so much. Growing up, finding even a couple of Bushtits in the juniper patches west and south of town (Waterton, Red Rocks, Dinosaur Ridge, …) was a real nice surprise, and only happened once or twice a year.
So what happened in the interim? As you all know, they are now common in numerous locations all along the Front Range. What gets me is that these guys have hopped habitat preferences, as opposed to expanding along with habitat creep like the Blue Jay following “forestation” across the Great Plains. Up until that little pack of Bushtits came through the yard, they were always a “specialty” of the piñon/juniper belts of the southeast and West Slope in my mind in Colorado. Now I can see a growing population, for whatever reason, spilling into the urban areas with all of the native and ornamental conifers, but an outright move into cottonwood riparian areas, that makes no sense to me – I smell a thesis in there somewhere.
Any thoughts from the “old timers” who have been here throughout this shift would be welcomed. While stumbling on a rarity every so often is fun, these little evolutionary mysteries are what I very much enjoy about our hobby that is so linked to Nature.
Happy to Be Back,
Doug Ward
Denver
David Suddjian
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DAVID A LEATHERMAN
Welcome back Doug "Thick-billed Kingbird" Ward.
I still thick of bushtit as a special bird when I see one, mostly because of my indoctrination regarding their status when I moved here in the 1970s. But certainly they are a great example of a species that has changed dramatically.
Rightly or wrongly, I tend to interpret most "trends" or "changes" we see in Colorado birding world thru the filter of their food. Every time I've been able to figure out the food of bushtits, it tends to be small insects: things like aphids, scales, psyllids, the makers of galls, plus insect parasites and predators of aphids and scales. I've watched bushtits at the Denver Botanic Gardens working for long periods of time on soft scales in some of the oak plantings. Of course, live oaks of several species are common in the southern heart of the bushtit's historical range. Many oak species are considered "quality" trees by Colorado Front Range urban foresters/landscape architects, and they are universally recommended as replacements for overplanted, "trash" species like silver maple, poplars and Siberian elm. Thus, I think, similar to what you mentioned for the blue jay, oak plantings are probably part of local habitat change by humans of benefit to bushtits. Certainly we have a lot of ornamental junipers and pinyon pines landscaping our new subdivisions. They occur on every list I've ever seen of recommended "xeriscaping" (i.e. low water use) plants, AND they harbor aphids and scales, good for bushtits. Climate change would seem to be another factor. I'd guess the associated extremes we've been seeing (especially those that could be described as "warmer/milder") allow for better survival of insect food items, but also, importantly, stress woody plants in a way that makes them more vulnerable to colonization by insects in the first place. Warm and dry, plus a lot more people taking showers and watering lawns = shortages, restrictions..... and moisture stress in plants.
In short I would say Colorado is fast becoming part of the desert Southwest. If you research the last 50 species added to the Official State Checklist, an overwhelming majority of them are southwestern or southern. Black phoebe, black-chinned sparrow, Lucy's warbler and many others are examples. Black-chinned hummingbird, formerly only found south of Colorado Springs or on the West Slope, now breeds in Lamar and all the way up the Front Range to southern WY. White-winged doves are now part of the scene. I saw 42 in one Lamar yard this past January. We had 13 roadrunners on the John Martin Res CBC last December. Steve Mlodinow found one near Fort Morgan a few years ago, one has been running the roads near Red Rocks in recent years, an unsubstantiated report came from west of Fort Collins a little over a year ago. If that was a fig newton of somebody's imagination then, it won't be in a few years. White-throated swifts overwintered in Pueblo last year. I think we are close, if it hasn't happened already, to having several species of shorebirds overwinter on open water in Colorado (least sandpiper, greater yellowlegs, spotted sandpiper, Baird's sandpiper, not just dunlin, snipe and killdeer).
It is exciting to see new things, but the reasons for them should be somewhat sobering. I think we birders have an important role to play in documenting the changes. If and when we ever have political leadership that values the environment, who knows, birders might have a lot to contribute that could make a difference.
Welcome back, and we also welcome your future contributions to COBIRDS.
Dave Leatherman
Fort Collins
Sent: Sunday, February 26, 2017 11:31 AM
To: cob...@googlegroups.com
Subject: [cobirds] Front Range Bushtits-What's Up Wtih That?
Doug Ward
David,
Thank you for the welcome back. I too am very much enjoying these little guys being around - always brighten up the day when they wonder through the yard.
I share your thesis that the changes in distribution and abundance, like we are seeing with the Bushtits, is due to a climatic shift. Up in North Idaho where we live (splitting time now), we are seeing a general northward (& eastward from the coast) march in a number of species (Anna’s Hummingbird, Lesser Goldfinch, Bewick’s Wren,…) similar to what you mentioned here. The difference between all of the species you mentioned, along with those we are seeing in the Northwest, and the Bushtits here, is that all of the for mentioned are following habitat corridors that are becoming available either through a shift in habitat health or more favorable wintering conditions; both points that you mention. The Bushtits on the other hand seemed to have flipped some sort of adaptation switch such that they have ventured out of their traditional habitat here in Colorado into new realms and are obviously finding astonishing success - this is the fascinating facet for me. Several folks mentioned the feeding of suet may be a factor, and it could well be (like more feeding of hummingbirds in the Winter in the NW), but we were feeding suet “back-in-the-day” as well and the only feeders that would get them were in places like Morrison, so who knows.
End of the day, I’m going to continue to get excited when I bump into a group of Bushtits as they represent the fact we really don’t know how Nature works over time. Thanks again for the welcome back.
Good Birding,
Doug Ward
Denver