Snowy Plovers, Least Terns, Nests & Chicks: Malibu Lagoon, 25 June, 2017

Lagoon channel view to south towards Malibu Colony (L. Johnson 6-25-17)

The Snowy Plovers and Least Terns nesting on Surfrider Beach next to Malibu Lagoon continue to be the big news. As mentioned last month, Snowy Plovers haven’t nested anywhere in Los Angeles County since 1949 in Manhattan Beach. Least Terns have nested for decades in the Venice Beach – Playa del Rey area, but we have no prior records at all of their nesting at Malibu save for a single attempt in 2013, when the parents left after crows ate their eggs.

Royal Tern flies out, Brown Pelican juvenile flies in
(J. Waterman, left; R. Juncosa right; Malibu 6-25-17)

Having them both nesting on the beach at the same time is a Significant Event. We can’t be sure exactly why they choose to nest here, but in my humble opinion it’s because the beach crew stopped grooming a long section of the beach nearest the lagoon. This left a lot of wooden detritus which provides cover, and allowed plants to grow, most notably Sea Rocket Cakile maritima. The wood and plants provide cover and protection from both elements and predators. A featureless well-groomed beach – lacking flowering plants, detritus, pebbles, small dunes and wrack – provides nothing.

Snowy Plover father & chick among the timber (R. Juncosa, Malibu 6-25-17)

Not all has been songs and roses for the birds.

Snowy Plover juvenile, almost certainly hatched elsewhere and recently arrived at Malibu (G. Murayama 6-25-17)

The average mortality across bird species is 90-95% in their first year, including time spent as an unhatched egg. We’ve already witnessed much mortality over the past month. The Snowy Plovers lost their first pair of eggs almost immediately. Of the next clutch of three, the first two hatchlings vanished within a day or two. At 22-days-old as of this field trip, the remaining chick has another 6-10 days before it is able to fly. The adult male may leave at this point or stay with his now-juvenile offspring up to an additional two weeks. The juvenile in the photo above, recently arrived on Malibu Beach is already on his/her own. Today we saw a total of five Snowy Plovers on the sand: the father and chick, an additional unbanded adult bird, and two juveniles.

Snowy Plover father & chick on sand hillock (J. Waterman, Malibu 6-25-17)

The Least Terns had apparently all mated and were nesting with eggs when Friday night’s new moon high tide of 7.03 feet sent waves washing over the nesting area, sweeping away all the eggs. Nothing was left on Saturday except one single chick. The adults were fine, but with possibly fourteen nests and 2-3 eggs per nest gone, they may have lost as many as 41 eggs. That was Very Bad News for the birds, and caused much consternation among their human observers.

The surviving Least Tern chick (J. Waterman, Malibu 6-25-17)

There was often a parent standing nearby.

Least Tern parent and chick (R. Juncosa, Malibu 6-25-17)

Fish appropriate as food for chicks are much smaller than those used for courting. If such small fish can’t be found, chicks will starve as they cannot swallow the much larger courting-sized fish.

Least Tern with smaller fish, possibly destined for the chick
(R. Ehler, Malibu 6-25-17)

Fortunately, Least Terns are resilient, and the pairs who had lost everything began courting and mating again the very next day. They were still at it on Sunday.

Least Terns mating (G. Murayama, Malibu 6-23-17)

I’ve been recording the field trip tide data for decades, and I thought a 7.03 ft. high tide sounded extremely high.  I checked my records and sure enough, of 119 high tides recorded, only twenty were over 6 ft. and two over 7 ft. Highest high tides occur: in the winter months when the earth is closest to the sun; at new moon and full moon when the earth, moon and sun align; at night, when the mass of the earth and sun align to pull on the oceans. There are two high tides and two low tides per day, and the higher of the two highs is at night.

The chart above shows the highest monthly tides bracketing our June field trip dates for the past five years and all of them are at night. So my field trip tidal data – and my feeling that 7.03 feet was extraordinarily high – is valid for late mornings, but not at all representative of nighttime tides, which are always, or nearly always, higher than daytime high tides. I suppose that’s why the grunion swim ashore at night to mate and lay eggs rather than during the day.

Least Tern & Top Smelt (J. Waterman, Malibu 6-25-17)

Rosi Dagit of the Resource Conservation District of the Santa Monica Mountains kindly identified the fish the Least Terns dangle and wave so blithely as [probably] Topsmelt (Atherinops affinis) so-called because they swim up near the surface. They also frequent nearshore waters – a perfect target for Least Terns. [I doubt the Topsmelt enjoy thinking of themselves that way.] Topsmelt are not a true Smelt (family Osmeridae) but along with Grunion (Leuresthes tenuis) are in the Neotropical Silversides family (Atherinopsidae ), comprised of about 110 species in 13 genera, distributed throughout tropical and temperate waters of the New World. [Fun Fish Fact: In the class Actinopterygii comprising all fishes, there are at latest count 46 orders, 533 families and 32,024 species of fish in the world according to {partially} Catalogue of life.]

Karen Martin, Biology Professor at Pepperdine University in Malibu, adds:

Least Tern pair fish-courting (J. Waterman, Malibu 6-25-17)

Families of ducks – Mallards and Gadwalls – are out and all about the lagoon. We found this squeeze-pack of ducklings on the lagoon edge between the PCH bridge and the northern observation point. Are they Mallards or Gadwalls? I can confidently reply…Yes!

Closely-packed ducklings – seven or maybe eight (R. Ehler, Malibu 6-25-17)

Farther out upon the waters were these two families, and I don’t think either of them are the group above.

Two duck families: Mallard, Gadwall or both?
(J. Waterman top; R. Juncosa bottom; Malibu 6-25-17)

The bird below is not wearing mittens.

Male Red-winged Blackbird whose feet are infested with Knemidokoptes mites (R. Juncosa, Malibu 6-25-17)

Kimball Garrett, Ornithology Collections Manager of the Natural History Museum of Los Angeles County says:

Your Red-winged Blackbird is afflicted with Knemidokoptes mites, which cause the “scaly-leg” condition. We see this fairly often in blackbirds (especially Brewer’s), as well as in American Robins and some other species.  It seems to be most noticeable in flocking passerines, perhaps because it spreads more easily in birds that live in large flocks.  Phil Unitt at San Diego Natural History Museum has been doing some wok on the historical development of the effects of this mite on birds in California, but I don’t know where that research stands. Severe infections can result in the loss of toes or feet, which can obviously reduce survival chances in affected individuals.

And you thought you had problems.

A very colorful Western Sandpiper in alternate plumage, either still on it’s way north or already back from breeding (G. Murayama, Malibu 6-23-17)

Last, not least, but unphotographed, there seems to be a Hooded Oriole pair nesting at the lagoon. I saw a female on June 17, flying east over the picnic area near Malibu Colony and diving into Bougainvillea next to a house. On June 25, Randy and Polly Ehler heard and saw a male fly over the parking lot, heading for the same picnic corner. I’ve searched the nearby palms but so far have not seen any light brown pendulous oriole nests. If you spot the nest, let me know.

Birds new for the season were: Great Egret, Long-billed Curlew, Heermann’s Gull, California Gull, Royal Tern, Hooded Oriole.
Many thanks to our photographers: Randy Ehler, Lillian Johnson, Ray Juncosa, Grace Murayama and Joyce Waterman.

Song Sparrow
(J. Waterman, Malibu 6-25-17)

Our next two scheduled field trips: Malibu Lagoon 8:30 & 10am, 23 July; Malibu Lagoon 8:30 & 10am, 27 August.

Our next program: To Be Announced, 3 October, 7:30 pm; Chris Reed Park, 1133 7th St., NE corner of 7th and Wilshire Blvd. in Santa Monica.

NOTE: Our 10 a.m. Parent’s & Kids Birdwalk meets at the shaded viewpoint just south of the parking area. Watch for Willie the Weasel. He’ll be watching for you and your big floppy feet.

Links: Unusual birds at Malibu Lagoon
9/23/02 Aerial photo of Malibu Lagoon

Prior checklists:
2016: Jan-June, July-Dec 2015: Jan-May, July-Dec
2014: Jan-July, July-Dec 2013: Jan-June, July-Dec
2012: Jan-June, July -Dec 2011: Jan-June, July-Dec
2010: Jan-June, July-Dec 2009: Jan-June, July-Dec.

The 10-year comparison summaries created during the project period, despite numerous complaints, remain available on our Lagoon Project Bird Census Page. Very briefly summarized, the results unexpectedly indicate that avian species diversification and numbers improved slightly during the period Jun’12-June’14.

Great Blue Herons: Juvenile left, adult right (J. Waterman left; R. Juncosa right; Malibu 6-25-17)

Many thanks to Randy Ehler for his contributions to the checklist below.
[Chuck Almdale]