Look, a Hawk!

When a hawk is called out, bird-watcher or not, everybody turns their head and wants to see it. Even a botanist who is concentrated on plants will oblige and allow him/herself to be distracted for a minute. Perhaps being both prey and predator in our evolution history makes us feel simultaneously threatened by and attracted to a ferocious hunter on wings.

After several years of watching birds in the Botanic Garden, we have come to realize that Alnus (Alder) growing on the west bank of Wildcat Creek at the edge of Sierran Section is a favorite perch of Sharp-shinned Hawk (Accipiter striatus) and Cooper’s Hawk (Accipiter cooperii).

A juvenile Cooper's Hawk on Alder tree, September 3, 2018. Minder Cheng.

These two hawks are small in size, and skilled in weaving in and out of dense woods to catch songbirds for meals. Foliage and branches of broadleaf trees are great cover for the stealthy snipers. Once they strike, successfully or not, they do not linger, but fly away immediately to either finish the job or find another hideout.

Although every hawk discovered is a cause of elation, the larger it is, the more excitement it arouses. Red-shouldered Hawk (Buteo lineatus) is much bigger than Cooper’s and Sharp-shinned Hawks; moreover, it is photogenic. Our local subspecies (elegans) has orange-red breast and belly, so distinctive and conspicuous once you locate it in the tree. On a memorable day in November 2019, we spotted an adult Red-shouldered Hawk sitting in Fraxinus velutina (Velvet Ash). We were mesmerized by its beauty, and it didn’t seem to mind our goggling. It was silent for maybe half an hour, then suddenly burst into calls. We didn’t know what caused it to announce to the world its existence, but we were thrilled to have a magnificent hawk displaying its full regalia and its vocal talent.

Adult Red-shouldered Hawk, November 5, 2018. Bill Thomas.

In fact, we hear Red-shouldered Hawks more than we see them. Their sharp and penetrating kee-ah series have a ringing quality, and often continue for some time before stopping. Listen to this recording made by Denise Wight in Tilden Park.

The wildlife harbored by the Garden makes it a great hunting ground for Red-shouldered Hawk, whose varied diet includes small mammals, birds, amphibians, insects, and crayfish. Several times during our surveys we saw this large raptor flying quietly down the canyon of Wildcat Creek, moving from one tree to another along the water course. And more than once did we see the carcass of crayfish lying on the rail of the wooden bridge crossing the creek. No witness came forward to identify the killer, but Red-shouldered Hawk is definitely a suspect in these unsolved murder cases.

Red-tailed Hawk (Buteo jamaicensis) is even larger than Red-shouldered, and is by far the most commonly seen raptor in the Garden. It usually appears as a fly-over that circles above us, glides effortlessly in the thermals or drifts along the horizon. Imagine our surprise when an immature Red-tailed Hawk showed up on the roof of the nursery next to the solar-powered well pump. It was on a weekend, and many visitors of the Garden walked by oblivious to its fierce gaze. The young hawk seemed just as unconcerned by people, paying its full attention to movements on the grassy meadow below.

Juvenile Red-tailed Hawk, intent on movements of rodents in the meadow. September 9, 2018. Minder Cheng.

Judging from its deflated crop (a pouch in bird’s gullet where food is temporarily stored after being swallowed), the fleet-footed voles and gophers that lived underground had largely evaded its talons.

Using sounds for bird identification is the game of experienced birders, and sometimes the only recourse to successful identification (especially so for Empidonax flycatchers). However, here birders encounter the challenge of mimicking. Steller’s Jay often throws me off by a bewildering array of sounds it is capable of making, which includes the masterful mimicry of hawks. And Red-tailed Hawk seems to be its favorite target of imitation.

Go to the second to the last recording on this page for a Steller’s Jay’s excellent parody of Red-tailed Hawk.

Why does a jay want to sound like a hawk? Donald Kroodsma says in Birdsong for the Curious Naturalist (2020): “Ornithologists have no solid answers, but are prone to speculate, of course. Maybe the jays are trying to scare other birds, or trying to warn their jay companions of a hawk or other danger nearby. Then I wonder, how often do jays call like hawks when we humans are not there to hear them?”

Next time you hear a hawk calling from somewhere in the trees, take note of the vocal quality. If it is a little too scratchy, not forceful enough, and doesn’t repeat a good number of times, then the calls may not come from a hawk. Try to follow the sound to its source, you may find a hidden jay singing away.

Extra:

Do you want to test your Accipiter ID skills? The difference between a Cooper’s Hawk and a Sharp-shinned Hawk is the perennial puzzle faced by hawk watchers. The following pair of photos were taken in the Garden; one has a Cooper’s and the other a Sharp-shinned. Please tell us how you decide which is which in comments. The answer will be posted after 3 days.

Note:

Jerry Ting and Bob Lewis, two esteemed birders in our area, helped me with Sharp-shinned Hawk and Cooper’s Hawk identification in many photos.