Saturday, January 12, 2013

SCIBERRAS, A. (2012) Fauna regarded as domestic pests in the Maltese islands (10) - The Feral Pigeon. The Malta Independent, December 17th pg 4-5.


We Maltese in general rarely see birds locally as pests, but we tend to see them as welcomed visitors and while a minority enjoys their company by observing them in the wild, the majority love to enjoy them gathering dust on shelves as sport trophies. I am more than sure that the practice of shooting birds has struggled to continue for the latter reason and not for food consumption. Therefore, birds should be considered much less as pests. Arnold Sciberras writes.

Locally, the only three species usually considered as agricultural pests are the following three species: the Spanish Sparrow (Passer hispaniolensis), Għasfur tal-Bejt, is usually considered a pest in fields as it gathers in large numbers to feed on agricultural products. It easily gets used to objects installed to scare it. In fact local farmers tend to nick name it as ‘ġurdien bil- ġwienaħ’ (mouse with wings), and this is because of the latter’s destructions and also due to its cunningness of a mouse. The only nuisance caused by this bird as a domestic pest is that it tends to see ventilators as the cradle for its offspring. Besides the nest which sometimes makes a foul smell, other arthropods usually follow within it. Nest material tends to be bulky, blocks the ventilator and nest material starts entering the house. Despite all this, it is illegal to disturb in any way this species as it is protected by law. Nearly the same applies for the Starling (Sturnus vulgaris ) Sturnell, except that it does not breed in ventilators and that in some time of the year it may be legally recognized as a bird applicable for hunting.

On the other hand the Feral pigeon, (Columba livia domest) Ħamiem Selvaġġ, is considered to be both an agricultural and domestic pest, and most tend to blame the latter for fouling  most facades of buildings within towns and cities and for carrying certain diseases. As agricultural pests, they eat adequate quantities of agricultural products and they tend to spread diseases from one farm to the other. Most farmers nick name pigeons ‘firien tas-sema’ (rats of the sky).
Feral pigeons are derived from domestic pigeons that have returned to the wild. The domestic pigeon was originally bred from the wild Rock Pigeon, also known as Rock Dove, which naturally inhabits sea-cliffs and mountains. All three easily interbreed. Feral pigeons find the ledges of buildings to be a substitute for sea cliffs, and have become adapted to urban life and are abundant in towns and cities throughout most of the world.

Many city squares are famous for their large pigeon populations. Such city squares include the Piazza San Marco in Venice and Trafalgar Square in London. For many years, the pigeons in Trafalgar Square were considered a tourist attraction, with street vendors selling packets of seeds for visitors to feed the pigeons. The feeding of the Trafalgar Square pigeons was controversially banned in 2003. However, activist groups such as ‘Save the Trafalgar Square Pigeons’ flouted the ban, feeding the pigeons from a small part of the square .The organisation has since come to an agreement to feed the pigeons only once a day, at 7.30am. In the Maltese archipelago this species is fairly abundant in all localities but tend to have impressive numbers at Valletta, Floriana, ta’ Xbiex, Imsida, Ħamrun, Victoria (Gozo) and on Comino (caves under pig farm and the cliff and islet known as Tal-Mazz).

Pigeons breed when the food supply is good. For wild Rock Doves this might be seasonal so they usually breed once a year. In the wild they are often found in pairs in the breeding season but usually they are gregarious. In the urban environment, because of their year-round food supply, feral pigeons will breed continuously, laying eggs up to six times a year.

Feral pigeons can be seen eating grass seeds and berries in urban areas and gardens in the spring, but there are plentiful sources throughout the year from scavenging (e.g. dropped fast-food cartons) and they will also eat insects and spiders. Further food is also usually available from the disposing of stale bread in many locations by restaurants and supermarkets, from tourists buying and distributing birdseed, etc. Pigeons tend to congregate in big groups when going for discarded food, and many have been observed flying skillfully around trees, buildings, telephone poles and cables, and even moving in traffic just to reach it.

As a result of the continuous food supply, pigeon courtship rituals can be observed in urban areas at any time of the year. Males on the ground initially puff up feathers at the nape of the neck to increase their apparent size and thereby impress or attract attention, and then they single out a female in the vicinity and approach with a rapid walk while emitting repetitive quiet notes, often bowing, sweeping their opened tails on the floor and turning as they approach. Initially, females invariably walk away or fly short distances while the males follow them at each stage. Persistence by the male will eventually persuade the female to tolerate his proximity, at which point he will continue the bowing motion and very often turn full- or half-pirouettes in front of the female. Subsequent mating is very brief, with the male flapping his wings to maintain balance on the female. Sometimes the male and female beaks are locked together.

Buildings are used for nesting as are cliffs and other natural sites. Favourite nesting areas are in old or damaged property. Mass nesting is common with dozens of birds sharing a building. Loose tiles and broken windows give pigeons access. They are remarkably good at spotting when new access points become available, for example after strong winds cause property damage. Nests and droppings will quickly make a mess of any nesting area. Pigeons are particularly fond of roof spaces, many of which accommodate water tanks, though they frequently seem to fall into the tanks and drown. Any water tank or cistern in a roof space needs to have a secure lid for this reason. The popularity of a nesting area seems little affected if pigeons die or are killed there; corpses are seen among live birds, which seem unconcerned.
On undamaged property the gutters, window air conditioners (especially empty air conditioner containment boxes), and external ledges will be used as nesting sites. Many building owners attempt to limit roosting by using floating empty plastic bags held by thin rope, bird control spikes and netting to cover ledges and resting places on the facades of buildings. These probably have little effect on the size of pigeon populations, but can help to reduce the accumulation of droppings on and around an individual building.

Feral pigeons tend to vary tremendously in plumage colours. Some of these morphs were even named and even local variants are known to occur. In Malta the author observed over 7 different morphological morphs that are generally persistent to occur.

This species belong to the family Columbidae. In Malta 7 species are recorded, all of which are protected by law except one which is hunted seasonally and the feral pigeon. These species are: the Woodpigeon (Columba polumbas) Tudun Ewropej, the Rockdove (Columba livia) Tudun Tal-Ġebel (ancestor of all domestic and feral pigions; most probably, Rock Doves do not occour locally as a pure breed), the Stock Dove (Columba oenas) Tudun Tas-Siġar, the Turtle Dove (Streptopelia turtur) Gamiema Komuni, the Collared Dove (Streptopelia decaocto) Gamiema Tal-Kullar, the Palm Dove (Streptopelia senegalensis) Gamiema tal-Ilwien/tal-Palm and the Barbary Dove (Streptopelia risoria) Gamiema tal-Bar/Ġar (originated from escaped stocks).

Pigeons have been falsely associated with the spread of human diseases. Contact with pigeon droppings poses a minor risk of contracting histoplasmosis, cryptococcosis, and psittacosis. Pigeons are, however, at potential risk of carrying and spreading avian influenza. Although one study has shown that adult pigeons are not clinically susceptible to the most dangerous strain of avian influenza, the H5N1, other studies have presented definitive evidence of clinical signs and neurological lesions resulting from infection. Furthermore, it has been shown that pigeons are susceptible to other strains of avian influenza, such as the H7N7, from which at least one human fatality has been recorded.

Note: This series of articles was intended to cover and give a brief overview of the most common groups of local species that regarded as pests. Obviously much more species than those mentioned in this series are regarded as pests in our islands and some have high economic value. I coined the articles as ‘domestic pests’ to cater those that have an impact on domestic households and other establishments.
Those pests that have an impact on the agricultural sector can be one of these listed in the series or others that are more specific to the latter. Unfortunately there are several other species that are all except pests, most of which are beneficial, but due to their appearance, habits and association with superstitious beliefs, they are regarded as pests. Most of these species are also protected by law. The emblem representative of the latter may be the geckos, (wiżgħat). I would like to thank Romario, Jeffrey and Esther Sciberras for their general assistance in compiling this work.

For more information: http://arnoldsciberras.blogspot.com ,bioislets@gmail.com or 99887950.

No comments: