07 Jun May 2017 Yellowbill
Tuesday, 9 May 2017, 7:00 p.m.
A Century of Avifaunal Change in the Fresno District
Jeff Davis — Colibri Ecological Consulting
John G. Tyler documented the status and distribution of birds on the floor of the San Joaquin Valley in Fresno County, California (the Fresno District) in the early 20th century. His work culminated in the publication of Some Birds of the Fresno District, California in 1913 and its supplement in 1916. That landmark publication provides a unique opportunity to assess avifaunal changes in a sizeable portion of the San Joaquin Valley over the last 100 years. I evaluated changes among 170 species that are or were year-round, summer, or winter residents by comparing Tyler’s assessment of their abundance and distribution in the early 20th century
with what we observe today. I found that 59% of these species have increased in distribution and abundance, 25% have decreased, and 16% have either not obviously changed or increases in some areas have been proportionally offset by decreases in other areas. I attribute these changes to four main causative factors: (1) artificial impoundment of water in numerous locations across the region; (2) expansion and maturation of urban, suburban, and rural ornamental trees, shrubs, vines, and herbaceous plants; (3) loss of natural land cover to urban, industrial, and agricultural uses; and (4) a change to clean farming practices (e.g., removal of weeds and non-agricultural habitats), all of which represent the major forces that have affected the birdlife of the San Joaquin Valley in general.
I was injured last month and unable to publish the April issue of The Yellowbill, so this issue contains Jeff Davis’ county bird reports for both the April and May issues, plus my report on the last Audubon California board meeting. I hope everyone was able to get the information they needed through our eblasts in the absence of the newsletter. The May issue is the last before or summer hiatus, and I would like you readers to weigh in on the need for a newsletter in the future. It takes many hours to lay out the newsletter using expensive software that only runs on a single computer and that cannot easily be transferred to another. Except for the bird report for Fresno and Madera counties, all the information found in the newsletter is also distributed by individual eblasts. Do you think we could discontinue the newsletter and replace it with a blog? Please send your thoughts to rsnow@ fresnoaudubon.org. Our 50th anniversary party was a great event. Many people helped make it a success, especially Jackie Folsom who coordinated the event. Other key helpers were George Folsom, Lynn Hemink, Susan and Greg Estep, Rich Gilman, Nancy Griesser and Barbara Bailey. Jane Manning found local businesses who donated items for our auction, including Trader Joe’s and Les Schwab. Gary Woods donated framed prints of his photos and Rich Gilman donated an owl box he built. We raised $1,477 from the auction! Thanks to all who bid on the items.
This month’s speaker is Jeff Davis. Jeff will tell us about the changes in bird abundance and distribution in Fresno county over the last 100 years, and the results may surprise you. This will be the last general meeting until September so I hope you can attend.
I hope everyone has a great summer.
February 16, 2016 to March 15, 2017
by Jeff Davis, photos by Gary Woods
Two Horned Grebes at Madera Equalization Reservoir March 10 (ph. GW, GF, RS) provided our second record this
winter. Representing our first record this winter, a Yellow-bellied Sapsucker, still retaining some juvenile plumage,
was at Lost Lake Park March 10 (ph. NE). This species has been detected at Lost Lake now for three consecutive winters, remarkable since the first one ever detected in our area was only 10 years ago. The male Vermilion Flycatcher at the River West Open Space Area north of Palm and Nees avenues continued through March 9 (ph.
m.ob.). Our first Western Kingbird of the season was near San Joaquin March 9 (ph. GW), five days ahead of the
long-term average. A Black-throated Gray Warbler at Reedley College February 23 (DJ) represented our fourth
Black-throated Gray Warbler
this winter, well above the average of less than one per winter. A male and female Hooded Oriole in central Fresno
Hooded Oriole Gary Woods
February 26 (KM) had presumably wintered in our area as the first migrants typically don’t arrive until the second week of March.
If you make an interesting observation, we’d love to hear about it. We are especially interested in birds listed as casual or rare on the Fresno Audubon checklist and those found out of season, out of normal habitat, or in unusually large numbers. Please submit reports to Jeff Davis (246-3272, firstname.lastname@example.org) or to the Fresno County Birders e-mail list, or e-bird.
Nelson Ernst, George Folsom, Daniel Jeffcoach, Kris McNew, Rick Saxton, Gary Woods
ph. = photographed by, m.ob. = multiple observers