English and Scientific names:

California Gull, Larus californicus

Number of individuals: 

1 1st year bird, probably with mostly juvenile plumage molting into 1st basic. 

 

Locality: LOUISIANA: 

Cameron Parish

Specific Locality:

about 1/4 mile East of Holly Beach community

 

Date(s) when observed:

Saturday, October 25, 2003

 

Time(s) of day when observed:

at mid-day

 

Reporting observer and address:

 

Paul Conover

501 Adrienne

Lafayette, LA 70506

 

Other observers accompanying reporter who also identified the bird(s):

Dave Patton

Light conditions:

Overcast but not dark. Lighting was very good for viewing gulls

Optical equipment: 

Zeiss 10x40's, Kowa 20-60 zoom, Sony camcorder linked to Kowa scope.

 

Distance to bird(s): 

From 20-50 yards.

 

Duration of observation:

1/2 hour perhaps, if not longer. Viewing was interrupted at least 3 times by passing vehicles which spooked flock.

 

Habitat: 

Open sand beach which was hosting a mixed flock of about 100 Laughing Gulls, 15-20 Herring Gulls, 3 Lesser Black-backed Gulls and a number of terns.

Behavior of bird: 

The bird was on the far side of the flock when spotted. It flushed twice as we were approaching it in our vehicle, due to the passage of other cars/4 wheelers. Each time it merely flew out, curved around, and settled back with the flock. It was easy to track in flight, as only it and a 1st winter Lesser Black-back had whitish rumps. We were finally able to approach it fairly closely. 

Description: 

A gull intermediate in size between Ring-billed and Herring. It was in a first year plumage, either juvenile, or entering 1st winter. The overall impression was of a brownish bird with dark wings and a dark tail set off by whitish rump/uppertail and undertail.

Structurally it had a small, round head and thin bill, and fairly long wings when folded, extending beyond the tail.

The bill was whitish-pink, a very unique color among the birds on the beach that day, with a distinct black tip which was slightly more extensive on the lower mandible. There was also a thin dark line on the upper mandible running parallel to the cutting edge of the bill at about the same level as the nares. The angle of the gonys was shallow, barely interrupting the straight line of the lower mandible, although the darker tip created the impression of a blob-tip.

The forehead rose in a curved, not angular slope, and extended into a gently, evenly curved crown.

The head was streaked or mottled brownish, lighter than the distinctly thick brown smudge of a hind collar. An area covering the forecrown, lores, malar region, and chin and throat was less heavily streaked than the rest of the head and was therefore paler.

The breast and belly were fairly evenly smudged brown to just behind the legs, the undertail coverts were whitish with dark subterminal V's giving a somewhat barred look. The tail appeared to be solidly dark brown. The pale uppertail coverts  were visible only when the bird was in flight, and contrasted the with the tail and mantle. I was unable to make out the exact pattern of the rump and uppertail.

The mantle was heavily marked with feathers of at least a few patterns, including some feathers which appeared evenly but narrowly striped, and some with subterminal brackets with dark shaft lines extending centrally. These bracketed feathers had a white ground color and white tip and I assume they were 1st basic feathers.

The folded wings in general appearance blended with the brownish tone of the mantle, although the ground color (a beige or peach color) of the lesser and/or median coverts seemed to predominate over the dark mottling of these tracts, creating a narrow pale longitudinal "blaze" on the sides of the wings that contrasted not vividly but noticeably even to the naked eye at a distance. The primaries were dark brown. The tertials were dark brown with pronounced paler edges, some that seemed whitish and some that seemed brownish with a fine dusted texture—possibly two generations of feathers were represented here. The greater coverts were brown, patterned with jagged paler markings distally.

In flight, the open wing showed dark brown primaries and secondaries. On extremely close inspection the primaries seemed to show very slightly paler markings on the inner webs of the very innermost primaries, just enough to notice but not enough to create a pale inner primary panel as in Herring Gull. The overall affect of the flight feathers was an unbroken dark brown stripe. The primary coverts were the same dark brown as the primaries, with a thin white edge apparently, as there is a hint of a wingbar there. The greater coverts on the spread wing showed dark bases, with a paler line distally created by the paler markings on their edges. The combined effect was of a second dark bar running parallel to the secondaries, slightly lighter than the secondary bar and separated from it by a paler line (a wing bar, in effect) created by the pale internal markings on the tips of the greater coverts.

The median and lesser coverts were paler brown, contrasting somewhat with the flight feathers. In flight, the impression created by the dark wings, pale rump and dark tail showed some similarity to a 1st winter Lesser Black-backed.

The legs and feet appeared grayish, and both Dave and I perceived a bluish cast. Field guides list the leg color of first winter California Gulls as pinkish; I have no idea if the bluish gray color was a function of the overcast, or if leg color in 1st years is variable.

The eyes were dark brown. 

 

Voice:

Not heard.

 

Similar species:

Ring-billed Gull is smaller, with a much different dorsal pattern.

Herring Gull is generally bigger, with a different head and bill shape, usually an all dark or indistinctly bi-colored bill in 1st winters, and distinct pale panels on the inner primaries. There were many Herrings in comparable plumage for direct comparison. 

Photographs or tape recordings obtained?

Videotape from which stills [included] were taken. Because the video was taken in overcast, the stills have a grayscale quality. The viewing of diagnostic features shouldn’t be compromised by lack of color.


photos

Previous experience: 

None in Louisiana, and none since November 1993, but I shot good video of many of all ages on the West Coast at that time which I refer to frequently. I also have extensive experience with the most likely source for confusion, Herring Gull, including probably hundreds on the day of this sighting.

Identification aids: 

at time of observation:

We looked at Sibley and one of the editions of the Geographic guide later than the 2nd. Neither was helpful.

After observation: 

I looked at pictures of California Gull on the Internet and found a great many pictures of 1st years which displayed a wide variety of looks. I compared individual feathers tract for tract and found a match for every marking.

Notes made during the observation 

Probably comments on videotape. Most features can be seen from stills. The rest are from memory.

Are you positive of your identification? If not, explain: 

 

Yes.

Reporter: 

Paul Conover

Date and time: 

7:48 PM, October 26, 2003.

Permission to display report and accompanying documentation?  

Yes.