Guest Post: Why Do Kingbirds Prefer to Dine on Drone Bees?

This post was contributed by Stephen Klotz, co-author of a recent paper in The Wilson Journal of Ornithology on Western Kingbirds preying on honeybees.

a watercolor painting showing a man watching out a window as a gray and yellow birds hunts honeybees
Klotz’s watercolor illustration of Schmidt’s experimental setup.

Justin Schmidt called me one morning and asked me to make a painting illustrating the “experimental setup” outside his office-cum-insectarium located in his home. A Western Kingbird was capturing honeybees in flight whenever they left a paper-mache beehive he had invented and manufactured.  He had seeded the hive with the lactic and citric acid, which attract bees, and hung it on a mesquite branch alongside a picture window. Several weeks later, a swarm had settled in. Justin could stand at the window in his office and observe the traffic from the hive once it became occupied. (Wild honeybees in Arizona below the Grand Canyon, incidentally, are all Africanized “killer bees,” and some swarms are prodigious in size.) Soon a Western Kingbird began perching on an adjacent mesquite branch and spent the day leisurely feeding on honeybees, returning for several weeks. Justin, whose long career included studying honeybees, quickly spotted that the bird was feeding exclusively on drones. Justin and the bird recognized the drones by their slower flight and very large heads and eyes.

Justin quickly discovered that the bird was leaving behind tangible data that he could handle, study, and record. The kingbird was regurgitating the exoskeletons of the honeybees within small one- to two-centimeter tubular pellets cast out on the ground below the perch site. Justin collected them each day and confirmed that only drones were being preyed upon, not workers. The latter are, of course, armed with stingers and require more dexterity from a would-be predator. He reasoned that the worker bees were not eaten due to the venom sacs that contained mostly mellitin, but he was uncertain why the bird preferred to feed on drones. In typical Justin fashion, he solved the enigma by sampling both worker and drone bees himself and found to his amazement that the drones were “soft, creamy and tasty” like a “cream cheese,” whereas the workers with their venom were bitter-tasting fare. Justin was meticulous about entering records into his field log daily, and all the data was saved along with several plastic tubes filled with casts of drone exoskeletons that had been regurgitated upon the ground by the Western Kingbird. This bird was able to distinguish the sex of the bees while in flight, a feat matched only by Justin.

Justin finally decided he wanted to write up the data for a journal. He and I have written over forty publications together on a variety of topics, including honeybees (“killer bee” attacks, to be specific), and both of us had spent many hours in his insectarium observing and measuring kissing bug feedings and defecations. I had provided illustrations for some of the previous publications, and so Justin asked that I do the same for this report. I sketched out several images for him to choose from. Before painting the image, I watched a number of YouTube videos of Eastern Kingbirds regurgitating insect exoskeletons but received no inspiration. As I began painting, I realized the coarse, thick, watercolor paper that I had chosen didn’t allow me to capture fine details, although it nicely showed Justin’s red hair as he gazed through binoculars at the Western Kingbird. In the painting, a drone bee is shown leaving the handmade hive, and another drone is in flight toward the bird. This was somewhat of a challenge since the size of these objects of interest (Justin, drone honeybee and Western Kingbird) varied widely. It was difficult capturing what distinguished all three figures from one another. Justin approved the painting and sent it off with the manuscript to WJO. Justin became ill about a month later and passed away in February, but prior to his death, he had the good fortune to learn that his last manuscript was in print.

This entry was posted in guest post by Wilson Ornithological Society. Bookmark the permalink.

About Wilson Ornithological Society

The Wilson Ornithological Society (WOS) is an international scientific society comprising community members who share a curiosity about birds. The WOS produces the quarterly Wilson Journal of Ornithology as the latest iteration of scientific journal publication supported by the Society since 1888. The WOS is committed to providing mentorship to both professional and amateur ornithologists through sponsorship of research, teaching, and conservation. Find us on, Facebook, Twitter, and Instagram (@WilsonOrnithSoc).

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s