Date: 7/2/26 3:34 pm From: Kim Thorburn via Tweeters <tweeters...> Subject: Re: [Tweeters] eastern WA birds moving west
Hi,
These are interesting observations. I like to think of these data in terms of conservation and clearly, habitat alterations and loss are well recognized threats to biodiversity. An important question for conservation is understanding adaptations made by species in response to habitat changes and how management might boost adaptation. Natural selection is a form of biologic adaptation but there are also other innate traits that contribute to adaptation and that are more amenable to conservation management.
Range expansion or transition is an adaptive mechanism to habitat alteration, especially for a taxonomic class as mobile as Aves. It may not require genetic selection. Is there evidence that lazuli bunting, chipping sparrow, and yellow-breasted chat populations have significantly declined in eastern Washington as more mobile individuals push into western Washington? Perhaps less habitat is pushing species, especially more habitat generalist species, beyond historic ranges as an innate compensatory response to habitat loss. Irruption, for example, is a behavioral response to temporal habitat changes.
I've been interested by some more micro, within-range observations. One example is wildland fire recovery. This week, I spent a day birding at Swanson Lakes Wildlife Area that was devastated by the 2020 Whitney Rd fire. The area was fairly intact basin shrubsteppe before the fire. Management, including plantings and weed control, assist fire recovery in some parts of the wildlife area but it is a large piece of land and much is untouched since the fire, including the area I was walking. Perennial bunchgrass recovery is far greater than shrub growth, which is spotty and hasn't achieved the size of the plants before the fire. Basin wildrye is a large bunchgrass that seems rather fire resistant and fast growing. I was surprised to find the patches of wildrye full of Brewer's sparrows. I've always considered them as shrubsteppe-obligate species reliant on sagebrush but their numbers have remained stable after the fire, unlike sage thrashers that have drifted from the area to places with unburnt sagebrush. It is not apparent that the shift in habitat usage by Brewer's sparrows required genetic selection. It seems more likely it was an already present innate adaptive mechanism. If the observation were to hold up, it might contribute to habitat protection and restoration practices. Basin wildrye is also important to other shrubsteppe species. Savannah and grasshopper sparrows use it and were present in substantial numbers during my walk. Some ground-nesting birds use it for nest sites. I often flush mule deer does stashing their fawns in the patches during this time of year.
Insect populations decline is a global phenomenon that is complex and multifactorial. Indiscriminate insecticide use is a contributor but invertebrate ecology is incompletely understood and habitat degradation is also a major factor. Insecticide use is definitely a controllable conservation management tactic, probably including a ban on nicotinamides. Unfortunately, though, reversal of the phenomenon won't be so simple. Much more needs to be learned.
Biodiversity conservation is intensively data dependent and birds are wonderful indicators. eBird data are useful and systematic data collection, such as the USGS Breeding Bird Survey, is essential. Biologic research like Jeff Kozma's work with white-headed woodpeckers makes important contributions to conservation management on multi-use lands. All such information is important to biodiversity conservation in eastern Washington that has proportionately less public land and more land conversion than other intermountain West basin states.
Some of my thoughts,
Kim
Kim Marie Thorburn, MD, MPH
Spokane, WA
(509) 465-3025 home
(509) 599-6721 cell-please use for texting
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From: Tweeters <tweeters-bounces...> on behalf of Dennis Paulson via Tweeters <tweeters...>
Sent: Tuesday, June 30, 2026 6:46 PM
To: TWEETERS tweeters <tweeters...>
Subject: [Tweeters] eastern WA birds moving west
Hello, tweets.
Looking in the eBird report, the amazing number of Yellow-breasted Chats reported in western WA recently stand out. Redstarts seem more frequent, Lazuli Buntings are seen all over the place, and we discussed earlier the many Chipping Sparrows turning up west of the Cascades, So I came up with a simple hypothesis to explain all these birds that we have long considered eastside birds that are turning up on the west side.
I hypothesize that the tremendous and ongoing destruction of eastside habitat, especially at lower elevations in the Columbia Basin, may be sending these birds westward. I have been here for over 50 years, and the changes east of the mountains have been horrendous from the standpoint of the environment. Not only has so much habitat been destroyed, but because of the use of pesticides in agriculture, the insect populations have surely been reduced to a tiny fraction of what they once were.
It’s quite possible that natural selection is playing a part in this, with birds on the west side more likely to have a successful breeding season, and their young returning to where they were raised. Presumably an analysis of the Breeding Bird Survey results would furnish a lot more data to test my hypothesis.
