Park Week 6/9/23

Killing Grassland Birds

Table from Knowable Magazine

Bird populations are in trouble worldwide, research shows, and the hardest hit are the grassland birds. We’re killing them by mowing their habitat, or converting it to agriculture and drenching it in pesticides. An article in the current Knowable Magazine reviews decades of studies on bird populations, showing that “a shocking number of birds are in trouble.” Apart from wetlands, where birds are increasing, every habitat is a graveyard for bird species. None is more deadly than grassland, where three quarters of the bird species ate headed toward extinction.

Of the 90 acres in our park, almost all of it is grassland. The forested oasis of the Native Plant Area covers a bit over 3 acres. The paved pathways eat up a fraction more. Then the 17 acres of the Off Leash Area are kept mowed for the convenience of dog owners, removing this grassland area from usefulness as bird habitat. Some additional acreage for kite flying and picnicking — maybe six acres — also needs to be mowed. That leaves, as a rough guess, 60 acres of grassland that can serve as grassland bird habitat, if we let it.

Grassland birds are ground nesters. In the park, the key ground nesting species are the Savannah Sparrow, the Song Sparrow, and the Western Meadowlark. They build their nests on the ground surrounded by grasses or other vegetation at least a foot high. They may fabricate roofs of grass over the nest and build access tunnels, sometimes several feet long, to disguise the nest’s location. Breeding, nesting, brooding, and feeding hatchlings typically keep the birds busy from March through June or July, depending on the species. In the park, grassland breeders favor the broad meadow on the east side stretching from Spinnaker Way on the south end up to the Flare Station on the north end. They seem to like the gentle slope of this meadow, the abundance and mix of its greenery, and its modest shelter from the prevailing westerly wind. Research by the Cornell Lab of Ornithology urges that protecting open coastal grasslands is the highest priority because Savannah Sparrows are most successful at reproduction in these habitats. “Grassland management, particularly mowing regimes, is critical” for maintaining populations.

How is our park doing at protecting grassland birds? Last week, mowing machines destroyed the entire grassland south of the Flare Station, and every nest in it. Earlier I could walk past this meadow and hear the high trill song of Savannah Sparrows everywhere in this grassland. This week, the land is silent.

P.S. Well, almost silent. On Wednesday, I saw to my great relief that at least two of the Savannah Sparrow parents were still present and hadn’t flown off. I saw them initially on the water side of the paved path. Then one of them, probably the male, flew across the path and into the mowed field. Maybe he was looking for their nest. At one brief moment, he raised his head and sang. See photo below. I wish I were Dr. Dolittle and could hear whether it was a song of mourning for his babies, or a song of anger at his tormentors, or what.

Savannah Sparrow singing in mowed field 6/7/23

Having your nest destroyed by a mower may be similar to having your home with your babies blown away by a hurricane. A growing body of evidence says that animals, including songbirds, can get PTSD, and over time, the stress leads to fewer offspring with less robust constitutions. Source.

I am grateful to Dominik Mosur, who reports that Savannah Sparrows have been nesting in Chavez Park for many years, probably even while parts of it were still a landfill. These birds are famously philopatric, meaning attached to a particular area and returning there despite adverse circumstances. For this tenacity we may be grateful.

Some Birds Saved

Another way to kill birds is to do nothing about windows, especially on tall buildings. An estimated 100,000 birds are believed to die from glass collisions in Berkeley every year. Tuesday evening City Council passed an ordinance that will slowly reduce this passive massacre by requiring new construction of larger buildings to install bird-safe glass on windows and other reflective surfaces. Read details in Berkeleyside here.

Featherapist of the Week

Following up on the Washington Post story that listening to birdsong is effective therapy for mental health issues, song birds have assumed a new role. They are now feathered therapists, or featherapists. Here’s a current practitioner holding forth on the north edge of the park. There’s no charge.

Song Sparrow (Melospiza melodia)

High Color

It’s breeding time for the House Finches (Haemorhous mexicanus). You can hear them twittering all over the park. At breeding time the males attain the peak of their color. The females look at color intensity as a token for good DNA and provider quality. Here’s two that probably had no problem getting dates on finch Tinder. Note those big beaks.

Pelicans at Last

Brown Pelicans 6/5/23

The Brown Pelicans have been back in some numbers for a couple of weeks, with individuals here even earlier. Where they are coming from isn’t exactly clear. The Cornell Lab of Ornithology’s Birds of the World source has considerable detail on their movements on the Atlantic Coast and in Baja California, but “Little known of migratory habits elsewhere in range.” In any event, they were here from about 7 in the morning, feeding by scooping in shallow water with their beaks. They weren’t plunge diving. As best I could see, they weren’t getting much beyond very small fry now and then. From 8:30 on they got restless, flying short hops to try to find better feeding patches, and by 9 they gave up and took off westward. I saw probably 25 to 30 of them. I did not see cooperation, such as their cousins the American White Pelicans sometimes show, advancing in a semicircle to drive fish into shallow water. But as always, they behaved peacefully with one another even when bumping elbows.

Two Blues

Photographer Susan Black remarked how small and slender this Great Blue Heron looked (below, left). It was most likely a youngster. These birds probably make their nests somewhere in the greater Bay Area, or south of here. Their migratory movements on the Pacific Coast are not well known. The bird in the photo on the right is clearly an adult. Note the heftier body mass. It has just caught some little wiggly creature, which will very shortly disappear down its gullet. Great Blues are effective foragers on land and in shallow water.

Plants of Note

The flowers of the California Buckeye (Aesculus californica) light up the Native Plant Area like candles. Put in the ground by the pioneers who built the area in the early 1980s, this tree could live 250-300 years. It’s native to California ranging up to Oregon. It will drop its leaves in late summer and go dormant, coming back in the spring. Its fruit, a chestnut, is the biggest fruit of any plant species north of the tropics. When properly leached and roasted, the fruit is edible. Raw, it’s toxic, and Native Americans would throw them into ponds to stupefy fish and make them easier to catch. California Ground Squirrels eat them without harm. The blossoms are a big magnet for butterflies. Native bees do fine, but honeybees (which were originally brought in from Europe) get in trouble. Source. Chavez Park Conservancy volunteers planted an additional Cal Buckeye in the Native Plant Area last November.

These dense, showy fingerlike white blooms belong to the Catalina Island Cherry (Prunus ilicifolia), a California native tree that produces edible but not delicious cherries in summer. Several of them grow on the south side of the Native Plant Area. The pioneers who established this area in the early 1980s planted them. They grow slowly but live a long time. The cherry has a thin flesh that’s mildly sweet over a large pit. Native American people fermented the fruit or made a jam from it, and mashed the seeds. Be careful not to confuse them with the red cherry-like fruit of the Ngaio tree (Myoporum laetum) which can damage the liver. Numerous native pollinators visit the Catalina Cherry.

The Seaside Woolly Sunflower (Eriophyllum staechadifolium) looks very similar to Yarrow, with small flowers tightly packed in heads atop longish stalks. In fact, it’s also known as Seaside Golden Yarrow, not to be confused with ordinary (non-Seaside) Golden Yarrow (Eriophyllum confertiflorum). But it’s not a yarrow. It is a member of the sunflower family. It is at home specifically in California. It’s very attractive to pollinators, especially butterflies. Chavez Park Conservancy volunteers planted it in the Native Plant Area in November 2021.

Creeks Plus

Our neighbor organization, Friends of Five Creeks, has put out another issue of its outstanding newsletter. Written by Susan Schwartz, the group’s president, the 8-page broadcast covers creekside weedings, a detailed lesson on pollinator flies, and a survey of regional, statewide, and a bit of national news affecting land and water. Download a PDF version of it here, or go to the organization’s website for more. This is the best habitat conservation newsletter in the region.

Squirrel of the Week

Munching on fuzzy plants can be so messy. The fuzz sticks to your hands and your chin.

This California Ground Squirrel (Otospermophilus beecheyi) is exhausted from its meal and too bushed to tidy up right now. I’ll do that later!

A park visitor the other day referred to them as “squirrel rats.” Earlier, another park visitor called them “water rats.” Oh, the calumny! Both rats and squirrels are rodents, but so are beavers, porcupines, guinea pigs, and hamsters. Note the obvious difference: the tail. Rats have naked tails. Squirrel tails are bushy. And think about timing. How often do you see wild rats out in broad daylight? Not much; they’re nocturnal. Squirrels are diurnal, like most humans. So quit the rat-shaming already, people!

Rats are said to be very intelligent, but that hasn’t kept them from being imprisoned and used by the many thousands in lab experiments. Squirrels have mostly avoided that. Who’s the smarter one?

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