A good question. The answer is something every Richmond resident should know, seeing as the heron is a symbol of our city.
Great Blue Herons and Sandhill Cranes, the one species of crane that may be seen here, are both mostly grey, about four feet tall, with long necks and scissor-blade beaks. But that’s where the similarity ends. They are very different in other aspects of shape, and also in behaviour and ecology. Evolutionarily, they’re much more closely related to other very different-looking types of birds than they are to each other.
Heron, of course.
A heron’s neck is usually to some degree kinked, and in flight the neck is almost always folded back so that the head rides upon the shoulders. Cranes are more straight-necked while standing, and fly with necks out-stretched. The adult heron has a thin, dark plume extending down the back of its head. Adult cranes lack a plume and possess a red, featherless forehead patch. The crane also has a “bustle,” a clutch of long drooping feathers that curls over the tail.
They move differently. Hunting in shallow water, herons are almost supernatural in their ability to stand perfectly still, waiting for a minnow to swim within striking distance. Cranes tend to keep moving with a rolling gait, picking their way along. In part this difference is related to diet. Herons are strict carnivores, eating fish, frogs, crustaceans, reptiles, small rodents, basically anything that comes along and will fit down their throats (and a few things that don’t; they’ve been known to choke on things too big). Cranes are omnivorous, will supplement their diet of smaller creatures with berries and grain. My young son was pursued by a savvy crane because he was carrying a paper bag of wheat seeds meant to be doled out to ducks. Should this happen, do as he did. Give up the bag. That beak is sharp.
There are other behavioural differences. Herons will almost never allow humans to get within several metres. Cranes can be more approachable. It is possible to walk among them sometimes, but there is a reversal in acceptance of human proximity when it comes to breeding. Sandhill Cranes build nests on the ground or on floating vegetation, in open, marshy areas throughout much of central and northern North America, including, at least historically, a few localities in the Lower Mainland. They bred on Lulu Island until the mid 1900s. Too much human activity will drive them away. Herons, on the other hand, will retain their sprawling tree-top heronries near to or even within urban areas. There are several large examples of their breeding colonies in Greater Vancouver, which is one reason why it is safe to assume that the single tall bird you see standing in a ditch is a heron, not a crane.
The fact that a bird is alone suggests heron. Although Great Blue Herons nest together, packing their nests onto tall cottonwoods or firs like chaotic Christmas tree ornaments, they are territorial when it comes to foraging. They’ll chase each other away from a perceived hotspot unless food is very plentiful. Cranes are more social. They arrive in a jubilant band, trumpeting madly. They forage and preen together.
Great Blue Herons are common here year-round, although their daily movements vary with the seasons, depending on whether or not they are nesting. An almost guaranteed way to draw one to your home is to install a koi pond in your backyard. They have expensive tastes.
Sandhill Cranes are never common in the Lower Mainland, but may move through during their long-distance migrations, and then can be seen along the foreshore or in farm fields. Small numbers may attempt to breed in the few suitable habitats remaining in the Fraser Delta, and there are two or three individuals that reside year-round at the Reifel Migratory Bird Sanctuary on Westham Island. They are usually not hard to find. They may even find you first if you’re carrying a bag of grain. When you see that red forehead coming at you, you know it isn’t a heron. You have met a crane.