(Left to Right): Little Egret (Egretta garzetta), Grey Heron (Ardea cinerea) and Intermediate Egret (Egretta intermedia)
Photo credit: Tan Rui Siang
Storks tend to have much larger bills compared to members of the heron family. Storks’ bills are also thicker and stouter and tend to curve up or down near the tip. Meanwhile, herons tend to have smaller, dagger-shaped bills that taper near the tip. 

Not surprisingly, the bill shapes of these birds are adapted to match their diet! For example, storks like the Asian Openbill Stork have bills that maintain a gap when closed, making it easier for them to extract their favourite meal, the golden apple snail, from their shells. In comparison, herons and bitterns use their bills as spears—rapidly striking fish swimming by.

Bitterns: Masters of Camouflage

Yellow Bittern (Ixobrychus sinensis)
Photo credit: Bok Wen Xuan

While birds from both families can be found near freshwater and coastal environments, storks are more likely to be found nesting on trees and feeding openly in fields and marshes. This is also true for most herons and egrets of the Ardeidae family. 

Bitterns, however, prefer to keep a low profile by hiding among reed beds that are found in well-vegetated water bodies. When alarmed, they adopt a “bittern-stance” by stretching their neck and head skywards. This helps them get a better sense of potential threats lurking in the sky and in front of them, while keeping them well-camouflaged amongst tall reeds. Remaining well-hidden in reeds also allow them to ambush prey more easily.

Foraging Behaviour: Passive Herons, Active Storks

Milky Stork (Mycteria cinerea)
Photo credit: Melvin Yap under CC BY-NC-ND 2.0 license

Grey Heron (Ardea cinerea)
Photo credit: Bok Wen Xuan

If you ever get a chance to catch these large wading birds in the act of predation, you may notice the differences in the way they forage for food.

Storks are relatively more active hunters than herons. Milky Storks (Mycteria cinerea), one of the three species of storks observed in Singapore, adopt the groping method as they hunt for their prey. They wade through shallow waters with their open bills submerged beneath the water surface, groping for fishes and frogs. The bills then snap shut when unfortunate prey makes contact with it, and the stork’s meal is then tossed into its mouth with a flick of its head!

Meanwhile, herons usually settle motionlessly along the water’s edge for a long time as they wait for an opportune moment to strike unsuspecting fish with their dagger-like bills. Eastern Cattle Egrets (Bubulcus coromandus) are also opportunistic predators and are known to dwell near grazing ruminants who may flush out insects for them to snag. 

Necks in Flight: The Determining Factor

Asian Openbill Stork (Anastomus oscitans)
Photo credit: Jayasri

Yellow Bittern (Ixobrychus sinensis)
Photo credit: Francis Yap

Intermediate Egret (Egretta intermedia)
Photo credit: Tan Rui Siang

Are the subtle morphological differences between herons and storks still befuddling you? The surest way to tell storks apart from herons and their counterparts is from their flight stances. 

Storks fly with their necks fully extended, while herons always retract their necks into a characteristic “S” shape while in flight. However, the retracted “S” shaped neck is more pronounced and noticeable in larger heron species than those of bitterns and smaller herons like the Striated Heron (Butorides striata) and Pond Herons (Ardeola sp.). These species tend to possess fluffy neck feathers that conceal their necks!

List of species observed in Singapore

Ardeidae			Ciconiidae
Herons	Egrets	Bitterns
Black-crowned Night Heron	Chinese Egret	Black Bittern	Asian Openbill Stork
Chinese Pond Heron	Eastern Cattle Egret	Cinnamon Bittern	Milky Stork
Great-billed Heron	Great Egret	Von Schrenck’s Bittern	Painted Stork
Grey Heron	Intermediate Egret	Yellow Bittern
Indian Pond Heron	Little Egret
Javan Pond Heron	Pacific Reef heron
Malayan Night Heron
Purple Heron
Striated Heron