When I got the call from the Lake Erie Metropark marina it was on a familiar topic. An egg had been found aboard one of the boats and the owner wanted to know what to do about it. Since sitting on it wasn’t an option, the response was to simply remove it. The offending layer was probably out of sorts anyway and looking to dump a few extra eggs. In any case, it wouldn’t have undergone incubation yet and was therefore prime for the frying pan. Once the boat was out of the slip, the situation would be ended.
In all previous cases the lone egg turned out to be a Mallard Duck egg dumped by a misguided female. This sort of thing happens quite a bit. This time was different, however. First of all, the egg was laid on the back portion of the boat at a place where the deck sloped toward the water. The only thing that kept it from falling into the drink was an electrical cord that lay across its path. Nestled in the uncertain embrace of the cord, the lone egg was held in precarious balance. So, it was an especially dim-witted duck, I thought. Then an additional mysterious fact popped up via the phone conversation. A pair of nervous Black-crowned Night Herons was hovering around the boat containing the egg. They refused to leave the vicinity and were acting very parenty.
Now, that was an unusual thing. I could not imagine a Night Heron laying a naked egg on the deck of a boat or acting in such a suspicious manner in mid-day. They are not called Night herons for nothing! I really wanted to check this situation out. The first thing was to check out the egg.
I had hoped that the staff would have kept the egg in position, but they opted to remove it before I arrived. In retrospect this was probably a good idea. If it had slipped from its uncertain position and into the green waters, I would never have had the opportunity to take a look at it. There, nestled in a cradle of paper toweling within a coffee cup, the mystery egg awaited my inspection.
At first glance I thought it to be a Mallard egg – albeit a small one. “No,” I was assured, “it matches the Night Heron eggs on the internet.” At the moment I recalled that Night Heron eggs were blue, not beige like this one, but momentarily backed off of my knee-jerk assessment. The internet never lies, right? I asked to be shown where the egg was found and was directed to the boat, the sloping deck, and the sad little electrical cord that once sought to save the egg (and perhaps had hopes to raise it as its own).
There on the adjacent dock sat the apprehensive looking Night Heron. The ruby red eye and long dangling head feather made for an impressive looking specimen. “The other one just flew away,” I was told. Sure enough, the other one returned as if to land on the boat but swerved away at the last minute upon spotting me. The first bird remained in its exposed dock position and eventually joined the other on the low branch of a nearby willow tree. By golly these two were acting very parenty indeed.
Black-crowned Night Herons are typically creatures of the dusk and night. These small herons typically roost by day and can be seen flying to their evening fishing grounds like giant bats in the twilight. Their primitive squawking calls heighten their mysterious demeanor. They nest in rookeries, like their larger cousins the Great Blue Herons, in large twiggy nests. All of this defies the situation before me. The birds were acting unusual in two regards.
I left thinking that maybe I was wrong and that the egg was a miscolored heron egg (an off color egg laid in an off color place by parents too ashamed to admit it yet unwilling to abandon it entirely). The only thing to do was conduct some serious consideration of the egg. This I did.
First of all, I compared it to the Black-crowned Night heron eggs in our collection. They were slightly smaller and blue. This one, as mentioned, was beige. Unfortunately the shade of beige tricked the eye into looking greenish bluish beige when placed next to the heron eggs, so the contrast was not radical. I then compared it to another mallard egg in the collection. That one was the same shade of confusing beige but was slightly larger than our orphan egg. Finally I did the math and eliminated all doubt. While the largest Night heron egg could be expected to be around 50 mm in length, this one was 55 mm long and wider by 10 mm than any recorded Heron egg. In short – it was a Mallard egg. The internet can lie if you just look at pictures, you see. The numbers do not lie (very much).
In this case we apparently had a pair of zealous birds who had grown used to fishing at the dock. They didn’t want to leave the spot now occupied by the boat in question. They were not acting parenty, as we thought, they were acting hungrily. There is even the possibility that the herons were looking to eat the contents of the egg and that we humans were in their way. But the fact is that they didn’t lay it. It was the human factor that brought the wrong egg together with the wrong bird. From heron in I shall be more careful in such situations.