Border protection

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Defending a territory in medieval times

Defending a territory in medieval times

Territorial behaviour is adapted to permit an animal to mate without interruption or to raise its young in an area where there will be little competition for food. It can also prevent overcrowding by maintaining an optimum distance among members of a population. Territories may be seasonal or can be occupied at all times. Male territories of some species may overlap with the territories of several females but are defended against other males.

All animals display territorial behaviour and that includes humans. However, we use different means to do so but that does not mean we are more effective. We humans have introduced laws and video surveillance, police and army to protect our family, our homes and our country. Animals don’t have that. They have to look to other means to do so.

Take our dogs for example, they mark their territory. When we take our dog for a walk it will frequently stop, sniff and mark the ground, a tree or a light pole. They use scents to discourage intruders. It does not much in their favour because another dog might have done the same just before yours and another one will do so after yours. By doing this they tell the next one that this is their territory, although they are no longer around to defend it. It becomes a different matter at home when someone tries to enter your property. According to a NSW Government report for the first three months in 2014 almost 1.8 million dogs were registered. 1,300 attacks were reported with almost 750 of them towards humans.

Australian Magpies Cracticus (Gymnorhina) tibicen are wide-spread in our cities due to the vast areas of well-watered lawns in lightly treed human-made landscapes. They are easily noticed because of their cheeky personality and their remarkable vocalisations. The German common name translates with ‘flute bird’ for a reason. Australian Magpies are well known for their habit of attacking humans during the spring breeding season for about six to eight weeks. It is one of the most common forms of human-wildlife conflict in Australia. This brood defence behaviour starts when the chicks hatch and ceases when they leave the nest, with an obvious increase in intensity as the nestlings grow. What some see as a bad-behaving bird is simply a natural reaction of a parent to perceived threats to their young. Attacking birds are almost always males acting within their ‘defence zone’ of an area between 110m to 150m away from the nest. While most attacks are harmless, few cause serious injuries and indirect accidents are not uncommon. Only a small minority of birds swoop and those who do, often have a preference for a few individuals which they recognise and target.

Black swans Cygnus atratus are graceful looking, large water birds and easily recognisable by their mostly black plumage with the exception of the broad white wing tips which are visible in flight. They are often seen to carry their wings raised in an aggressive display. The red bill has a distinct narrow white band towards the end and a pink tip at the end. The long, graceful, arched neck allows it to dip into the water and gather the aquatic plants and seeds that form the major part of its vegetarian diet. Black Swans nest in the winter months and both parents share the care of the nest. They are known to build nests in colonies but while this is the most social and least territorial of all swans they are quick to attack intruders near their nest. However, that aggression might only go towards a particular species while they exhibit no aggression towards other animals, which they share the area with.

Masked lapwings Vanellus miles novaehollandiae, also commonly known simply as “plovers”, are easily noticeable by their long reddish legs. The yellow wattles on the face, and the yellow bare skin that covers the forehead and the upper area of the eyes makes them unmistakably. They are easily recognised from afar by their loud, penetrating calls. Another important feature is the long and sharp wing spur which can be used as a defence mechanism. It has been known to inflict scratches on rare occasions. They pair for life and rarely move far from the established territory. During breeding season in late winter to early spring, both adults will swoop on intruders to defend their eggs and hatchlings. However, most swooping is more a threatening bluff to warn off intruders and contact is rarely made. After the young hatch the territory is no longer bound to a particular area but rather to a large mobile ‘home’ around chicks.

The Noisy minor Manorina melanocephala is a smart little bird that displays a different type of territorial behaviour. They live in smaller territorial groups within a loose much bigger colony and will unite to mob any predators. They are very successful at driving even much bigger animals away. Although they are known to chase away all other species from their territory I have not found it true in our garden. The Noisy miner is a bold and curious bird and easily identified by its yellow bill and the naked skin behind the eye contrasting the mostly grey body. The name is well suited as they are chirping away all day long but become very vocal when ganging up on intruders. Noisy miners are well adapted for life at the edge of areas of bush and the diverse array of large-flowered plants with abundant nectar found in many suburban backyards suits them very well.

Territorial behaviour is not restricted to mammals and birds. Other classes, like fish do exhibit this behaviour, too. This well-known behavioural characteristic in Betta splendens to fight with one another to defend their territory gave them their common name, Siamese fighting fish. For many centuries this trade was used in staged competitive fighting. Today the many colourful varieties make them a popular aquarium fish. These fish are endemic to Thailand and feed on zooplankton, mosquito and other insect larvae. Originally they live in standing waters of floodplains, canals, rice paddies and medium to large rivers. A special respiratory organ, the labyrinth organ, allows them to breathe air directly from the surface, which in fact they have to in order to survive. Therefore they do not depend so much on high dissolved oxygen levels of the water body. This has led to the common practise to keep them in very small containers. However this should be discouraged to give them a better quality of life. Males will fight each other and should therefore not be kept together in one aquarium. The female will be driven away after laying her eggs and can become in danger if the space is too small. In their natural habitat they have become threatened by habitat degradation and are declared vulnerable on the IUCN red List of Threatened Species. Genetic erosion from escaped farmed stock into wild habitats has become a secondary threat to them.

Betta (left) flaring at his mirror image (right)
Betta flaring at mirror image
Betta (right) flaring at his mirror image (left)

References:

 

  • Darryl Jones (2007). Wildlife management in the extreme: Managing Magpies and mothers in a suburban environment. Suburban Wildlife Research Group, Centre for Innovative Conservation Strategies, Griffith University, Nathan, Qld 4111, Australia.
  • Vidthayanon, C. 2013. Betta splendens. The IUCN Red List of Threatened Species. Version 2014.2. iucnredlist.org [accessed August 2014]