From: Justyn Stahl
Date: Sat, 05 Jan 2019 14:57:26 PST
Now that I have received and compiled all of the data for the 66th San Diego Christmas Bird Count, the final count stands at 216. Having already presented the highlights (https://groups.io/g/SanDiegoRegionBirding/message/9114), I wanted to dig into the data a bit and see if it reflected the general feeling that land bird numbers were down this year. In short, this answer is not really, most numbers of migratory land birds were in fact stable. A few were notably down, however. I’ve not gone into any intensive analyses or even corrected for observer effort, but simply compared 2018 numbers for select species to the 10-year average from 2008 to 2017. (My, how things have changed from the 1950s and 60s…) Below is a list of notable counts – high or low, or for select species, average. Take this all with a large shaker of salt…
Greater White-fronted Goose – A new high count this year with 27.
Ross’s Goose – A new high count this year with 3. (Note this species was reported initially as Snow Goose.)
Canvasback – Fourteen is a good count for recent years.
Ring-necked Duck – Just one reported in each of the last 3 years, with average of 14.
Nearly all waterfowl numbers were below 10-year averages, with Lesser Scaup and Northern Pintail at about one-third average.
California Quail – Just three, and while barely hanging on inside count circle, this species is a far cry from when it reached triple digits as late as the early 1990s.
Pacific Loon – News from up north suggests this species is perhaps in decline, and we registered just 59, with a 10-yr average of 320.
Black-vented Shearwater – Averaging 72, we only saw 4, although this species can simply move en masse offshore and outside the circle.
Double-crested Cormorant – About half normal.
American White Pelican – A new high count this year with 97.
Yellow-crowned Night-Heron – A new high count of 11.
White-tailed Kite – Although historically down, our count of 11 this year was equal to recent average.
American Avocet – Just 33, a near low, with average 105.
Snowy Plover – Some good news, 232 was well above average of 194.
Ruddy Turnstone – Apparently in decline, we had 18 (half normal) while Black Turnstone remains stable.
Dunlin – About one-third recent average, with 103 on count day.
Short-billed Dowitcher – We counted 166, about 25% average.
Red Phalarope – Missed some years, we saw 45, average is 184.
Cassin’s Auklet – I guess I didn’t realize how big of a deal this was at the compilation: our 6 on count day was the first observation since 1990!
Heermann’s Gull – Recent multi-year breeding failure may have cause our recent steady decline since 2015. We observed 178 this year, with 10-year average of 545.
Eurasian Collared-Dove – Thankfully stable at 124.
Great Horned Owl – The first miss for this species since 2002, but hopefully due to lack of effort.
Allen’s Hummingbird – Assuming the majority of Selasphorus hummingbirds reported were Allen’s, 232 would be a new high count for this species in San Diego.
Scissor-tailed Flycatcher- For two years in a row (new in 2017) we’ve recorded two individuals – having a known roost helps!
Loggerhead Shrike – This species is just hanging on with 3 (a far cry from the long-term average of 41, recent years’ average just 4.3), but generally in decline nationally.
White-breasted Nuthatch – An invasion year, with 15 being a very good count. Average is 2.8, and the high is 20.
Cactus Wren – Happy to report above average numbers with 13 inside the circle.
Blue-gray Gnatcatcher – A large count from the east edge of the circle along the Otay River pushed our total to 113, a new high count. Average is 37.
Ruby-crowned Kinglet – Above average numbers: 218 vs 166.
American Robin, American Pipit, and Cedar Waxwing all above average.
Orange-crowned Warbler – At average: 272 vs 277.
Nashville Warbler – Three was a new high count!
Yellow Warbler – Above average: 12 vs 9.
Palm Warbler – None known in days prior to count, and not found on the count, one made count week when found on December 16th in Manzanita Canyon. A shocking miss on count day, given what seemed to be the best fall on record for this species along the coast in southern California.
Yellow-rumped Warbler – This species was essentially at average: 3380 vs 3468.
Black-throated Gray – With 14 on count day, we set a new high count. Average is 7.
Townsend’s Warbler – With 77, we were at about 75% average.
Wilson’s Warbler – Average year, with 6 compared to 6.6.
Chipping Sparrow – Average year, with 34 compared to 33.6.
Lark Sparrow – Average year, with 7 compared to 8.8.
Dark-eyed Junco – Juncos were above average with 49 observed, compared to 34.
White-crowned Sparrows – Plentiful as always, apparently, with 1599 seen compared to recent years 1756.
Golden-crowned Sparrow – An average year is 8.9, we had 13.
Savannah, Song Sparrow, California Towhee – all about 75% average.
Summer Tanager – Essentially average, with 6 vs 6.5.
Western Tanager – A notable uptick, with 32 (a new high!), compared to average of 14 and past high of 25 (in 2014).
Brewer’s Blackbirds – Seemingly down, and actually down, 103 was half average.
Brown-headed Cowbird – An average year: 103 vs 104.
Bullock’s Orioles – Nearly a high (20), we saw 17, which was above average (9.9).
And last but not least…
Scaly-breasted Munia – Continuing to grow, we set a new high count with 89 this year. In 2017: 62. In 2016: 33.
And notable counts of non-countable exotics:
Red-masked Parakeet – While common in parts of the county, 7 in the count circle was a new high.
Black-throated Magpie-Jay – While some historically argued (surely no one still is?) that this species should be added to the State List, with a 2018 count of 8 and a historic high of 17, not doing so was the right decision.
Pin-tailed Whydah – Perhaps one to watch? New for the count, with just 3, but this species is popping up at a small number of parks in San Diego, and is already seemingly established in some parts of Los Angeles and Orange counties. This species presumably parasitizes munias, so its expansion with Scaly-breasted Munia makes sense.
Thanks again to all of the participants who make this long-term dataset more valuable each year.
Happy New Year,
San Clemente Island