Wild Secrets – Coastal Adventure After April Rains
By Richard Zembal, natural resources director for the Orange County Water District
Practicing field biology means time in the field. What one gets by reading, conversing, and study is important but it is only a small piece of the practice. It has always been a struggle, balancing the field and the office, but an understandable dilemma. Specialized trades must be practiced to develop and maintain one’s working knowledge but one must also author, review, sign, meet, collaborate, etc.
An outing is planned with purpose, accompanied by anticipation, expectation, and sleep-interrupting anxiety; it is executed adaptively with observation, interpretation, and documentation. The findings add to a growing database, prove or dispel theories, and lead to theory modification, additional scrutiny, and sometimes a new paradigm.
In the struggle to maintain or expand expertise, I spent a recent day off in a coastal wetland in San Diego, assisting with surveys of the wetland birds. The expertise developed during such exercises is “practice” for what we do with those same wetland birds as field biologists at the Orange County Water District.
Many of these kinds of bird are reclusive and documented by their vocalizations more than sightings. A bird’s call can yield more information than just a sighting, if the call, for example, is associated with territoriality and breeding. It takes regular practice to learn and remember all the calls of all the birds and exercise that expertise so that the mental muscle doesn’t turn to flab.
The particular lagoon I visited is undergoing restoration. I walked miles of trail that day, and my focus remained upon the secretive birds of the wetland but this tale is more about encounters along the way and the random musings those conjured.
Wildflowers were in abundant bloom that late April day, following the unusually heavy spring rains of 2020. There were golden sun cups; purple-ribbed blue-eyed grass; blue caterpillar flower, lupines, and wild Canterbury bells; red Indian paint brush, Scrophularia, and fuchsia-flowered gooseberry; and white popcorn flowers and wild cucumber. The complex floral patchwork displayed as a rainbow carpet.
Among the wildflowers was a small stand of coast barrel cactus, a rare San Diego County endemic that I had never observed in this wetland before. Then, looking towards the coastal dunes, I saw fields of yellow dune primroses. Our beach dunes were once covered in spring wild flowers but one common shrub has spikey fruits and bare feet are no match.
The remarkably heavy, abundant rains washed away soil and uncovered some of nature’s animal treasures as well. A rare find that April day was a woven tube with D-shaped lid still attached. A colony of California trapdoor spiders had been exposed by runoff, their tubular chambers left suspended above ground surface and a few had broken off. Their dwellings are woven silk inside, clay-lined outside and about ¾ inches in diameter, perhaps 8 inches deep. The lid is usually closed, unless the female occupant is watching for a passing, meal-sized arthropod; then, a couple of spider legs hold the lid open, a mere slit, vigilant hunter inside, ready to pounce.
Trapdoor spiders look like small tarantulas, but nearly hairless; glossy black but with a brown abdomen. They are dug up and eaten themselves by a variety of small mammals and are attacked by tarantula hawks, a colorful, large wasp that stings to paralyze them, lays a single egg upon them, and leaves them to be consumed slowly by the larval wasp. These spiders don’t particularly like being handled, are not prone to biting but apparently the bite is a bit painful, although not otherwise injurious.
Heavy late rains can wreak havoc with nesting birds. Some birds could be sitting on eggs during the warm spring breeding cycle when a late storm hits, plummeting temperatures with cold drenching rains and torrent-driven winds. Many early nests likely didn’t make it this season. A greater number of small white eggs from local birds could be seen lying about randomly. I generally suspect most to be mourning dove eggs.
Their nests are avian embarrassments, comprised of a scant number of barely interwoven twigs placed wherever. More often than not, the eggs are visible through their minimalist nests, yet these doves are typically successful breeders and nesters. They nest across the U.S.; build nests almost anywhere, even in hanging baskets on front porches; lay only two eggs but take meticulous care of those youngsters until they fledge; and they eat only seeds, producing crop milk that is fed to the nestlings.
Odd weather affects both resident birds like the mourning dove and migratory birds that nest here annually. Of the latter, the endangered California Least Tern, a summer resident, nests only on open sandy beaches on the coast well north of their wintering range.
But I wondered most about the California resident I heard announcing ownership of a coastal breeding plot, likely after having nested once this season already in the desert. The Phainopepla is an iconic Southwesterner, tied intimately to desert mistletoe berries and the supporting mesquite stands. But, after early breeding is complete in the desert, they fly off to the coast to breed again in summer. It was only late April when I saw them on the coast; was the desert round of breeding a bust in 2020 due to unusually heavy, late rains?
These incidental observations had little to do with my primary purpose on that late April day; they just happened along the way. What a great field day! I am recharged and only wish that you could have been there to share it with me.
This wildlife article was written by Richard Zembal, natural resources director for the Orange County Water District (OCWD). OCWD’s award-winning environmental programs benefit both nature and water supplies.