A few weeks ago Mom had a hankering for a hot fudge sundae from McDonalds. Now McD's is not my idea of fine dining (nor hers), but it is a family tradition of sorts. We grew up back in Chicago near the second McDs opened by Ray Kroc. Back then you got a shake, hamburger and fries for $0.47 and we'd all pile into the car and drive there. There was no dining area beneath the Golden Arches, you sat in your car and munched away. Instead of "billions and billions served," the count at that time was about 100,000! One of our Chicago neighbors, Hank Peterson, later created the Egg McMuffin which Mom loves.
Enough about my munching (and there would be nothing to write about any mating lately in my story). While we were enjoying our treat, I looked across the room and saw a bird outside staring through the window at the patrons chowing down. Of course I had my trusty HD camcorder with me, so I went over to film this rather amusing situation. There was not one, but two white cattle egrets outside lusting after the Big Macs. Cattle egrets are a type of heron, so you might expect them to be checking out the Filet-o-Fish, or heading over for the seafood at Red Lobster. However, cattle egrets are strange birds... they prefer terrestrial fare over fish and have a special relationship with cattle (hence the possible Big Mac attack).
The cattle egret (Bubulcus ibis) earned its common name because it is frequently seen associated with cattle. I'm referring to the cows that inhabit grasslands rather than sea cows. The genus name Bubulcus means "herdsman" in Latin. These herons reach 18-22" tall with a wingspan of about a yard. They have a thick yellow bill rather than the long, slender ones on most herons; dark legs and feet; a relatively short neck and often appear to be hunched over. Juveniles start off with a darker bill that turns yellow by their first autumn.
Most herons and egrets munch on my fine finned friends from the watery depths. However, the cattle egret has lost the ability to correct for refraction (bending of light) in the water, and they have difficulty targeting fish accurately. Although they sometimes feed in shallow waters, they rely primarily on tasty terrestrial delicacies such as insects. Grasshoppers, crickets, flies and moths are featured menu items but they will add spiders, earthworms and small vertebrates such as frogs to round out their diet. Ugh! Here is where grazing animals enter the picture. Cattle and other grazers provide food in two ways. First, they stir up insects in the grasslands making them easier targets for the egrets. Second, the birds can feed directly on flies, ticks and other critters that harass the mammals. This is an excellent example of mutualism, an ecological relationship between two species which benefits both.
The cattle egret was originally native to Asia, Africa and Europe. In many parts of its original range, cattle as we know them here in the States were not present until recently. Instead, the birds formed mutualistic relationships with a range of "partners" including rhinos, hippos, elephants, and zebras. They were much more likely to be called rhinoceros egrets or elephant birds in Africa, at least until cattle were introduced.
This species has experienced one of the most rapid, and generally natural, expansions of its range and is now quite cosmopolitan throughout much of the world. Way back in 1877, it flew across the Atlantic well before Lindberg and arrived in the NE regions of South America. It first arrived in North America in 1941, breeding in Florida, and has now spread west to Caleefornyia and north to Canada. About the same time it colonized Australia and then New Zealand. One reason for its extensive dispersal is that some populations of cattle egret are migratory and may settle in new areas. Another reason is they tolerate humans fairly well and may follow us as we migrate and introduce domesticated livestock in new areas. They are also well-adapted to urban environments as proven by their presence at McDs!
Rhinoceros (er, cattle) egrets typically breed when they reach the terrible twos. Nesting colonies are usually established in trees near bodies of water. Breeding adults develop orange-buff plumage and their legs may become bright red before pairing off. The male "displays" using ritualized behavior such as shaking a twig or pointing its bill towards the sky to announce himself to the ladies. Try that some night at the Marlin Club! They form pair bonds within a few hours... which I guess is an example of love at first sight. The male collects sticks and twigs which are arranged by the female to create the nest.
One to five bluish white eggs are laid in a clutch with 3-4 being the norm. Chicks are fully feathered in two to three weeks and fledge at about 30 days. They achieve independence from the parents at about 45 days. Examples of "brood parasitism" are known where a cattle egret will lay its eggs in the nest of another species such as a snowy egret, although apparently these eggs rarely hatch. Cattle egrets are "seasonally monogamous," staying paired up for the entire breeding season to raise their brood. However, they do not pair back up during the next breeding season and raise the next batch of youngsters with a different partner. Hmmm... I know some humans who do that too.
By the way, on a later visit to McDs to film the egrets a patron came out and tossed several French (remember, they helped us win our freedom 200+ years ago) fries out for the bird to munch on. I filmed the egret tasting one, but please... feeding wildlife, especially deep fried foods, is very inappropriate. I was pleased to see a McDonalds' employee come out and tell the customer not to feed the birds.
© 2011 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!
To return to the list of ALL of Dr. Bill's "Dive Dry" newspaper columns, click here.
Cattle egret tasting (ugh) French fries at McDs, then washing it down with a drink of rain water.
This document maintained by
Dr. Bill Bushing.
Material and images © 2011 Star Thrower Educational Multimedia