Gray-winged Trumpeter Psophia crepitans

  • Order: Gruiformes
  • Family: Psophiidae
  • Polytypic: 3 subspecies
  • Authors: Arjun Brandreth Potter
Sections

Behavior

Behavior

Dominance hierarchy

Trumpeters are highly social birds, and spend their lives in cohesive flocks. The details of the behavior of Gray-winged Trumpeters are little studied, but probably are similar to the behaviors of the Pale-winged Trumpeter (Psophia leucoptera), which has been studied in southern Peru. Trumpeter flocks have a defined dominance hierarchy and consist of birds of all ages and sexes. Dominance is recognized by means of a highly ritualized "Wing-spread" display, during which subordinate birds face a dominant bird, lower their heads, extend their wings horizontally, and give a call similar to the high-pitched twittering call of trumpeter chicks. This display is given by birds of all ages and is most commonly given just after dawn, a period during which birds fly down from their roost and reestablish their social rank for a few minutes. The Wing-spread display exposes the secondaries, which are darker on juveniles, and makes the bird vulnerable to attack, and thus a low-ranking bird seems to show a higher ranking bird that it is younger and subordinate. Dominant birds often respond to the Wing-spread display with a "Wing-flick," in which the folded wings are swiftly lifted up and forward and then brought down again.

In Pale-winged Trumpeters, individuals under three months old preform the wing-spread to all individuals, but older birds generally display to individuals of the same sex, maintaining a within-sex dominance hierarchy.

Territorial Behavior

Most of the day is spent roaming the forest understory in search of fruit and arthropods and patrolling the flock's territory. Should a flock detect a trespassing group of trumpeters, the flock will run very rapidly towards them. Sometimes the trespassers are chased off, but more likely the trespassers are caught and a fight ensues. While driving out trespassers, birds run towards birds of the same sex with their head down and their wings arched upwards and the primaries and secondaries drooping towards the ground, and proceed to alternately peck and then flap up and kick the intruding birds, ever after they have fallen down, until the intruder flees or fights back. This continues until the intruders are chased back into their territory. Males are more likes to fight, while females and juveniles often stand back and give the loud territorial trumpeting call. After the intruders are chased onto their territory, Pale-winged Trumpeter males in both groups will then make submissive Wing-spread and dominant Wing-flick displays and will even offer food to males of the other group. It is during this time that subordinate adult males will often switch between groups, but will return to his home group after a few weeks if he does not succeed in achieving a higher rank. It is thought that males do this to increase their chance of breeding, and as a result there is genetic mixing between groups.

Allopreening and Social Feeding

Pale-winged Trumpeters spend more time loafing in response to increases in their food supply, and forage more diligently when food is scarce. When food is abundant, groups move slowly, and stop often to preen and bathe and sun. Adult Pale-winged Trumpeters frequently solicit preening from each other by bowing their heads towards other adults, who then rapidly open and close their beak as they run it through the feathers of the head and neck of the receiving bird, removing parasites and dead skin. Juveniles will solicit preening from adults or other juveniles. It does not seem that rank explains the amount a bird solicits or receives allopreening.

Trumpeters will often use food socially, especially when it is abundant. Pale-winged Trumpeters have been observed picking up a piece of fruit or an arthropod and hold its head high and arch its wings and walk around repeating a single, medium-pitched call note. Adults of the same sex or juveniles will then lower their head and give the submissive twittering and the food-begging call. The feeding bird will hold the food above the begging birds for a few seconds to a few minutes before it is given to one of the begging birds. Instead of swallowing it, occasionally the recipient of the food will pass it back and forth with the food donor several times until one of them swallows it. Dominant birds will even beg for food from lower-ranked individuals, but if the lower-ranked bird does not give the food within a few seconds the dominant bird will snatch it away.

Play

Play, both solitary and social, is common among trumpeters, and much of it seems to mimic territorial squabbles. Birds will peck and kick at leaves and twigs, jump up in the air and flap, and run with the head lowered and the wings arched. When more than one individual plays they often chase each other between pecking at objects and will even face off and peck at each other without hitting, after which the birds split up and chase other birds. Birds tend to play for only a few minutes at a time.

Roosting

When night falls trumpeters fly 8-15 m up to roost in trees, and tend to spread out into different parts of the same tree or different nearby trees. Trumpeters roost in different areas each night.

Territoriality

Gray-winged Trumpeters live in small groups of roughly 3-15 members, and the group defends large year-round territories with stable boundaries from other groups, largely by means of territorial calls (see Vocalizations). In the related Pale-winged Trumpeter (Psophia leucoptera), territories were found to vary from 58 to 88 ha, with an average of 72 ha (Sherman 1995b). Trumpeters spend much of their day foraging and patrolling their territory, walking an average of 3.7 km per day in the case of Pale-winged Trumpeters. During conflicts over territory, the territorial call will be employed while chasing out intruders, who, after reaching their territory, give the territorial call in response. For more information on territorial conflicts, see the above section on Territorial Behavior.

Trumpeters generally roost in trees in different regions of their territory each night. The territorial call is given by roosting flocks starting two hours after sunset, and each group calls for one to two minutes. Birds call throughout the night at intervals of two and a half hours. Flocks that roost near each other will fly down to their shared territorial boundary and call vigorously at each other.

As all suitable habitat is usually occupied by one or another territorial group, it is extremely difficult for young trumpeters to start their own territories. This shortage of territories seems to help explain why trumpeters are cooperative breeders, as they may gain higher fitness by remaining in the home flock.

Territories are often quite large, as they must provide enough fruit to sustain the flock the whole year, even during the dry season when fruit may be less available. Territories often contain many different habitat types (see Habitat).

Sexual Behavior

Although all members of a flock assist with raising young, only a few birds breed, typically the single dominant female and a few dominant males breed. Breeding is proceeded by a good deal of courtship (female choice) and intrasexual selection (male-male competition).

In the related Pale-winged Trumpeters (Psophia leucoptera), ritualized feeding is part of a trumpeter courtship (Sherman 1996). The dominant male feeds the breeding female, but only during the breeding season, and during this time nearly all the food given to her is given through the dominant male. Most of the food he gathers himself, but some of it he steals from lower-ranking males.

Copulation is almost entirely confined to the breeding season. In Pale-winged Trumpeters, copulation begins six weeks before the female begins to lay. Eason and Sherman believe that for the first four weeks copulation is unable to fertilize the eggs: it follows then that males become increasingly protective starting the 2 weeks before laying, as the female is like receptive from this time until 24 hours before the last egg is laid. The three dominant males will guard the female from all other males and attempt to interrupt each other's copulation attempts. The dominant male obtains two thirds of all copulations, but he is unable to prevent the two next highest-ranking birds from stealing the remaining third of copulations. The Beta and Gamma males obtained 3/4 and 1/4 of the remaining copulations, respectively. In this way, the amount of genetic material passed on is proportional to a bird's dominance status.

In Pale-winged Trumpeters, males and females spend 5-10 s engaging in what appears to be solicitation prior to mating (Sherman 1996). The female crouches down and presents her rump to the male, while he walks in a circle around her while she turns to keep her rump facing him, until he mounts her and they copulate. Conceivably much of the same information above true for Gray-winged Trumpeters.

Social and interspecific behavior

Trumpeters are very vocal about announcing potential threats. Upon encountering a terrestrial predator, such as a human, the closely related Pale-winged Trumpeter (Psophia leucoptera) gives loud squawks as alarm calls and flees into dense cover. The presence of a snake is announced with a special call, and all members of a flock will stand together near the snake while calling for a few minutes, while aerial predators are announced with a different call. See Vocalizations.

Often reliant on primates, such as spider monkeys (Aleteles), capuchins, (Cebus), and squirrel monkeys (Saimiri), and to a lesser extent guans and curassows (Cracidae) and toucans (Ramphastidae) to knock down fruit and some insects, but trumpeters also usually actively follow monkey troops. Often commensals of army ants, feeding on the insects they flush. See Food.

Predation

Likely depredated by a wide variety of mammals, raptorial birds, and large snakes. Felids such as the Jaguar (Panthera onca) and Ocelot (Leopardus pardalis) likely take adults, while nests are likely raided by primates and coatimundis. Humans are a significant source of mortality in some areas, as trumpeters are highly sought after for food.

Recommended Citation

Potter, A. B. (2011). Gray-winged Trumpeter (Psophia crepitans), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.gywtru1.01