Long legs, long necks, and long bills – surely Herons, Storks, and Cranes must all be a part of the same family? As much as they may appear to be relatives, the short answer is that they actually come from three separate families. The morphological difference may seem to be subtle on the surface, but the other key features become more recognizable as you become aware of them. I recently provided a few tips to distinguish between Swifts, Swallows, and Martins and a good suggestion came up to do the same for these three bird families.
So what is it that is different about each family?
Well for starters, Storks and Cranes generally have very similar body shapes throughout the family. Herons come in two forms and can be either tall and similar to that of a Stork or Crane or short miniature versions. The three main short or small herons are the Striated Heron (previously Green-backed Heron) at 41cm and is commonly seen here at Londolozi, and two nocturnal species often seen along the Causeway when crossing the Sand River and are the White-backed Night Heron and the Black-crowned Night Heron.
On the tall side, you are likely to come across a Grey Heron (90-98cm) at almost any shallow water body across the reserve, while the world’s largest heron, the Goliath Heron stands on average at 1.43m tall and is hard to miss when they are around.
The Storks and Cranes also fall into the “tall” category with the Storks ranging from the Woolly-necked Stork at ~84cm to the Marabou Stork at ~1.5m (here at Londolozi) and the shortest Crane, the Grey Crowned Crane standing at 105cm tall. This makes it tricky to rely on height to easily distinguish between these birds. We can, however, eliminate Cranes from the mix here at Londolozi and simplify the identification process, as aside from their distinctive bulbous-shaped heads that often have elaborate ornamentation, they do not occur in this area or nearby regions.
This leads us to the bill shape of each family and thus their specific feeding habits and habitat.
The Storks, along with all their other lengthy features, have long, heavy and pointed bills that tend to curve up or down near the tip. Meanwhile, Herons still have pointed bills these are however shorter and taper near the tips. Herons will then use their dagger-like bills to jab at prey while they stand patiently or wade slowly through shallow waters waiting for their prey to come within striking range.
This hunting strategy differs from the aquatic Storks who actively search for prey. Storks, such as the White, Black, Woolly-necked, and Saddle-billed, will tend to wade through the water and then chase after and stab at or impale prey as they move past while the Yellow-billed Stork uses its sense of touch, walking with its bill open and partly submerged to catch prey. The Cranes on the other hand have short and laterally compressed bills adapted for the omnivorous diet of eating invertebrates, small vertebrates, and seeds associated with their terrestrial lifestyle in open habitats.
What else sets these three families apart?
Aside from the physical features, one other notable feature or lack thereof is the calls of these birds. Herons have well-developed voices, although the calls are usually described as harsh or raucous krannks and kuaarks such as with the Grey Heron. Storks, in contrast, have poorly developed voices and are mostly silent unless they use ‘ bill clattering during displays. This is when individual birds will open and close the bill with force, making an audible sound that is reverberated by the hollow structure of the mandibles. Cranes are known for their lower-pitched voice and elaborate, far-carrying calls that usually accompany a courtship dance.
A final tip…
Herons can easily be distinguished from Storks in flight as they fly with their head pulled in towards the body so that the neck resembles an s-shape from a side-on angle and appears to have no neck from below. Storks, aside from the Marabou Stork, instead fly with their heads extended from their bodies making their long straight necks visible from below. The tip here is to remember ‘Straight neck’ for Stork. So next time you are out birding, hopefully, the key features will be more familiar to you and help you to tick another Stork, Heron, or Crane off your birding list.