Hunting in group

Hunting in group: Harris Hawk REPORT

08 de august 2016 - Alessandra Oliveto / Translation: Jessica Tulio

Falconry is the science that uses techniques to train birds of prey with the goal of catching prey at their natural habitat. It’s considered by many as an art, given the high degree of sensibility and dedication that are demanded by its practice (ANF, 2015). In Brazil, falconry is not prohibited, however is not permitted either. There are specific laws that must be followed, for that the falconry’s techniques may be used in the country. (this can be a subject for the next text.)

Nowadays, we can hear lots about bird abatement companies, using hawks and falcons to catch the most variety of species that can cause any kind of damage to human beings.

BIRD ABATEMENT

Falconry has being chosen as one of the best solutions against conflicts when it’s about humans living together with animals that can cause environmental, economic and health nuisances. Falconry’s techniques train birds of prey that will chase animals that are “urban pests” (harmful synanthropic fauna), such as pigeons, house-sparrows, southern lapwings, etc.

The pursuit performed by the trained birds of prey shows an immediate effect on the unwanted animal population, since they feel threatened and abandon the infested areas.

Thus, in a simple, environmentally clean and friendly way, it’s possible to work around conflicts created by the human activity without resorting to condemnable methods.

The Falconer or trainer has the role of training the raptor so that it can capture potential preys and then replace that prey for a reward, which is usually a piece of meat.

The return that the falconer gets for all the work and dedication to a bird of prey is to watch it fly with such dexterity and maneuverability. The raptors acquire, during the days/years, a lot of flying experience, learn how their prey escape, what is better way to capture, how to take it by surprise and, if it´s a Parabuteo unicinctus, how to work in groups.

PARABUTEOS UNICINCTUS

The Parabuteos evolved to live socially and, according to the studies of Jennifer and Tom Coulson, they work in groups due to the challenging locations where they live in nature. When more challenging is the site, the greater is the Parabuteos groups.

An interesting feature of P. unicinctus is its ability to perform cooperative hunting, where two or more individuals attack along the same prey (Bednarz,1988).

When Harris´s Hawks forms a group, they also care about each other, according to reports from Jennifer, she observed a Parabuteo probably hurt perched while others were hunting. When the prey was caught, they took the food to the alleged injured bird. Robson Silva and Fábio Olmos, in their article written in 1997, reported that when they trapped a Parabuteo for studies, they saw 4 hawks perching next to the trap while an adult male perched in a post.

When the immature was trapped and the researchers approached, the adult male vocalized high, causing the others to flee.

PIGEONS

Pigeons have evolved to escape from predators. We remind here that F. pereginus, the fastest animal in the world, is a natural predator of pigeons, so the pigeons have to be adapted to escape from this clever and fast predator. One of the skills that we see in pigeons, besides the fast flight and great maneuver, is that their feathers come off very easily, which is an adaptation to evade from predators.

In many times, when slipping the Parabuteo in a pigeon, it gets many feathers on its feet, thinking that it caught something, but the pigeon is already flying far away.

A DAY IN BIRD ABATEMENT USING FALCONRY TECNIQUES

We started an urban pest control (pigeons) in a Convention Center that consisted of 2 large sheds attached to a building of the same size, but having 2 floors.

As we always do, we did an inspection in the entire building in the first day to know where all the nests and pigeons were on the site. The structure of these sheds tricked us, making us believe that there was fewer pigeons than we actually saw when we initiated the job.

There is no day like the other in Pest control, the birds surprises us in the solution of problems that they face to capture their prey, in the tactics used. This time, after talking a lot with Jennifer Coulson, I started to observe Harris’s Hawk’s social skills. And that’s why I decided to write this text.

The raptors flown by Falcontrol S.A has at least 2 years of experience with control, all of them were trained to lamping, carhawking, control in warehouses and control in open areas.

There is a lot of raptors working at Falcontrol, but here I’m only going to talk about three birds (P. unicinctus) used for bird abatement: Brisa, Sakura and Tanatus.

WHERE IT ALL BEGAN

Social animals form groups that can vary from temporary to permanent. Depending on the nature of these relations, which develops between these individuals, the result of these relations will form the behavior pattern of these animals.

Brisa and Sakura are sisters of the same clutch (FUKUI 2013) and they’re trained together by the falconers Dorival Lima and Eduardson Elias respectively.

They differ from each other, first because of their size and second because of their behavior. The name Brisa (Breeze in English) comes from her calm and serene behavior, like a breeze.

On the first season, as all young Harris’s Hawks, they fought each other sometimes e it was needed to always fly them together to get over it. Tanatus came here some months later at Maceió.

Brisa would always attack everyone during the flights to show superiority.

Sakura would always try to defend herself from Brisa and would knock her down from perches in the field. Until one day Brisa immobilized Sakura on the ground, showing dominance. (Fig. 1) La Leyenda del Áquila de Harris (Manuel Diego Pareja & Óbregon de Los Reyes; page 34).

TEAM WORK AND BRISA’S DOMINANCE

“Groups of animals often need to make common decisions, for example, about which behaviors perform, when perform then and which direction to take, however little is known about how groups make them.” (Conradt e Roper 2003)

Tanatus always followed Brisa in the field and it’s the first time they work together on control in the warehouse.

After getting them off of the transport boxes, Tanatus and Brisa made a low vocalization to each other, as if they’re chatting. Sakura is always in alert position, looking for pigeons and she doesn’t pay attention to the “conversation”.

We released all 3 in the warehouse and they chose what way to go, each one goes to the place where they had a sigh of a pigeon.

It´s noticeable that Brisa is the Alpha of the group. Sakura is rebellious and sometimes does not participate on the hunt. She prefers to hunt alone, but is always successful.

The tactic used by Brisa and Tanatus is: Tanatus position himself (sometimes hidden and sometimes stands still perched at the beam) at the end of the shed which has no pigeons and Brisa flies close to the shed´s ceiling in the central area to reach a beam before the pigeons (which are currently resting).

When she sees that it´s time, she flies towards the pigeons. The pigeons flies frantically towards the end of the shed and Tanatus is there waiting and slips on the pigeons or flies towards them.

Sometimes, this tactic works for Tanatus to catch a pigeon, but sometimes Brisa needs to go back and do it all again.

When this tactic starts to fail a lot, Brisa vocalize a thin sound and sometimes she would even fly towards Tanatus, as if she was saying: Hey, pay attention!

The second tactic is when Brisa and Tanatus uses three beams to corral the pigeons. Brisa perches in a beam, then Tanatus perches in a beam opposite to Brisa’s, and between them, there is a 3 rd beam where the pigeons are perched.

Brisa slips towards the pigeons, driving them to fly towards Tanatus, which drops down, where the pigeons are passing through.

Of course that’s only two techniques used by them to hunt in this shed.

Clearly we can see that the Parabuteos use the male’s sprint and the female’s flight constancy to hunt. The dominant one always have the attitude of being in front of the hunt.

THE DISPUTE TO BE THE ALPHA

A dominance hierarchy occurs in Parabuteos, which the mature female is dominant (ALPHA), followed by the adult male and then the young birds of previous years.

An unusual thing happened in this day. A pigeon was cornered in the shed and when we looked up, it was like a Parabuteo bowling to this corner and we only could hear the noise of the pileup. We don´t know exactly who caught the pigeon, who came first and who hit who.

We heard the bird’s vocalization, the pigeon flying bewildered and Tanatus appeared adjusting himself. Soon after came Brisa and Sakura disputing territory.

Wings spread, spiked head, vocalizing loudly, and throwing claws to the opponent.

Finally Sakura left the scene and Brisa went to the highest point of the shed and stood for a few seconds vocalizing, demonstrating who was the group´s alpha and finishing the work day.

In a study made by James W. Dawson and R. William Mannan there are several types of dominances hierarchies in Parabuteos groups and in 11% of the studied groups by them there was a second female dominant (alpha-2) that was subordinate to alpha female and dominant over the alpha male.

Maybe we evaluate the characteristics during this season that will begin and we draw a conclusion of how this group behaves, now being more mature. We will do the translation of the article "Dominance hierarchies and helper contributions in Harris Hawks" for the next post.

....

Oliveto, A.C et all (2015) A arte da Falcoaria. Brasil pp 18

Bednarz, J. C. (1988). "Harris' hawk subspecies: is superiorlarger or different than harrisi?". in Proceedings of the southwest raptor management symposium and workshop. Washington, D.C. pp. 294–300.

Conradt L, Roper TJ (2003) Group decision –making in animals. Nature 421: 155 – 158

James W. Dawson e R. Willian Mannan DOMINANCE HIERARCHIES AND HELPER CONTRIBUTIONS IN HARRIS' HAWKS