Reserva Ecológica Costanera Sur

Sitio realizado por aficionados a la observación de aves desde 10 de enero 2006

Feeding - Rufescent Tiger-Heron

Order: Pelecaniformes - Family: Ardeidae. Family commonly known as Herons.

The Rufescent Tiger-Heron is a resident bird at the reserve and lives together with other resident herons: Great Egret, Snowy Egret, White-necked Heron and Black-crowned Night-Heron. It is rather big, more than 60 cm tall. The long neck adopts the classical S shape of herons, though sometimes it may be hidden below its "mane". Its aspect changes radically if the neck is coiled or stretched. It is a solitary bird. It may be discovered in the grassland, where it conceals easily in the vegetation, exposed on the bank of the pond, or up in the trees, where it nests. It does not withstand human presence nearby. So, if it feels threatened it flies away. It hunts during the day and its diet is very varied: fish, eels, frogs, small mammals.

Hocó colorado/Rufescent Tiger-Heron© Julio Schindler Hocó colorado/Rufescent Tiger-Heron© Rosana Rodriguez Hocó colorado/Rufescent Tiger-Heron© Hugo Hulsberg Hocó colorado/Rufescent Tiger-Heron© C. y T. Di Mauro
From left to right: With Australoherus facetum, turtle, eel and rat. The Tiger-Heron of the last photo is a juvenile.
To hunt the Tiger-Heron uses the Stand and Stalk Technique. It can stay motionless for a long while waiting for the prey to come whithin reach. The typical hunting stance is with the bill in a horizontal position because the binocular field extends below and in front of the bill. So the bird can see what passes by in front of his feet. Binocular vision also guides the strike with precision. It can also be seen wading in shallow waters in search for food. It moves with long and slow strides. As it walks along it can keep the head still, an advantageous feature for this foraging technique. View animated gif

Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron
Left: Stalking with the bill in horizontal position. Motionless it waits for the prey, it locates it and "uncoils" its folded neck for the strike. Photos 2006 © Roberto Ares
The specialized neck morphology allows the Tiger-Heron to give and withstand this lightning bill movement. The neck muscles are aligned to move the neck forward and a series of ligaments minimizes the torque through a locking mechanism. Another feature particularly developed in herons with diurnal feeding habits is that they have the ability to compensate for refraction. This effect displaces the real position of a submerged object when it is observed from above the water.
Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron
The neck can adopt the S shape due to a specialized neck vertebra, which functions as a hinge to lunge the neck forward. It pounces on the prey with a step forward. A true fencer in action. Touché!, says the eel.

Photos 2006 © Roberto Ares


The Tiger-Heron captures the prey with the bill tip and paralizes it with a shake, so that it will not offer resistence. Then it moves it from the bill tip to the mouth to swallow it whole. It uses the tongue to secure it. When the prey is in the base of the bill, some muscles expand the gular region so that the passes through the esophagus. The Tiger-Heron stretches the neck to ease the prey down and if there is water available, a little sip is always welcome.
Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron
Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron
This juvenile Tiger-Heron has a rat in its bill tip. With some head shakes the Tiger-Heron paralizes it and moves it to the throat manipulating it with the tongue. In the first photo of the second line the expansion of the gular region can be appreaciated. Once swallowed, the expansion of the esophagus.

Photos 2009 © Claudia y Tito Di Mauro
Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron Hocó colorado/Rufescent Tiger-Heron
This wriggling eel did not give up so easily. The Tiger-Heron had to contend with it before subduing it. In the last photo it may be observed how the tongue secures the prey by adopting a convex-like form, which reaches the upper mandible. The gif animation shows the eel being swallowed and the little sip at the very end.

View animation

Photos 2006 © Roberto Ares