Reserva Ecológica Costanera Sur

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

Agonistic Behaviour - Wattled Jacana

Order: Charadriiformes - Family: Jacanidae

The Wattled Jacana is the only resident bird with polyandrous habits at the reserve. In this unusual mating system the female forms a harem. She chooses up to five males with which she mates simultaneously and separately in the territory each male owns. The male, instead, mates only with that female and he is responsible for building the nest, incubating the eggs and caring for the young. This means that in this case polyandry is associated with parental role reversal. A typical feature of this type of system is that the female is bigger in size than the male.

Jacanas are territorial birds. The pair defend the territory from intruders or other jacanas, which compete for resources. The male charges against any intruder within his territory. If he can not cope with the situation he calls the female for help. So the female interacts over a supraterritory consisting of her males´ territories.

This is a ritualized confrontation where there is no physical aggression. It consists of a "dialogue" of displays triggered by gestures, visual and/or sound cues which give rise to action and reaction.

The following 18 shots belong to the same conflict situation between a pair of jacanas and an intruder. It is divided in three parts: intruder´ attack and male´s defence, second intruder´s attack and male´s defence with female´s intervention, and final intruder´s withdrawal.

Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
The intruder steps into the scene with vocalizations and menacing posture. The wings are somewhat separated from the body to show off the spurs. The territory holder responds to the attack likewise (threat display). Considering the male´s attitude the intruder breaks visual contact (appeasement), and crouches to fly away (escape). The female does not actively participate.
Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
In the second attack the intruder repeats the threat, appeasement and escape displays. Nevertheless, a male´s cue makes the female get closer to take part in the conflict.
Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
Jacana/Wattled Jacana Jacana/Wattled Jacana Jacana/Wattled Jacana
A brief communication between the pair and the male resumes the defence. A light skirmish is enough to drive the intruder away. The territory holder has reasserted his dominance over his territory.

Photos taken in August 2006 © Roberto Ares