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Ducks, swans competing for natural habitat

The Mute swan is recognisable by its orange bill. Relatively silent, its few sounds are audible only a short distance away, and are similar to a puppy barking or a high-pitched whistle. In contrast, the pounding of the air to lift such a large bird is audible over long distances.

The Mute swan is recognisable by its orange bill. Relatively silent, its few sounds are audible only a short distance away, and are similar to a puppy barking or a high-pitched whistle. In contrast, the pounding of the air to lift such a large bird is audible over long distances.

Gozo woke up on Monday, Jan­uary 2, to 12 “swans-a-swimming” in the Marsalforn Valley. Driven south by a spell of cold weather, it was as if they had flown straight out of a Christmas carol.

The nature of our landscapes with small reservoirs, often walled-in, does not suit visiting swans very well. Seasonal ponds, which form in many valleys, dry up completely during the arid, summer months.

One of the swans was separated from the rest. It landed in Ta’ Żieta Valley, a narrow valley under the gaze of the Citadel, at the foot of a steep road up to Xagħra. Swans need a good long ‘runway’ for take-off on open water. This one was trapped.

A feral population of Muscovy ducks can frequently be seen swimming in the Ta’ Żieta Valley reservoir in winter. There is little concern that swans could become a problem here yet ducks could impact local ecosystems if numbers get out of hand.

Domesticated in pre-Columbian South America, Muscovy ducks were taken to Europe by Spanish conquistadors in the early 16th century. Known to make good pets in captivity because of their “peaceful temperament”, they can be shy in the open and downright aggressive if cornered.

The sudden appearance of a lone swan in duck territory must have ruffled the alpha male Muscovy duck of Ta’ Żieta Valley. It kept up an assault on the exhausted bird for hours. Sharp claws at the end of their webbed feet are for grasping tree branches, a favourite nesting site. Although not wild, they are capable of harming a creature as big as a swan.

Lucky for the solitary swan, it was pulled out of the reservoir just in time by a Gozitan hunter and relocated near the other swans.

The Muscovy duck is reported to be quite an omnivore with a taste for lizards, mice and small birds. This observation led to the Muscovy (or Barbary) duck being declared a predator and therefore non-kosher by certain rabbis.

Swan populations in other countries have had to be checked due to their environmental impact. Yet it is the Muscovy duck which poses the greater threat to local ecosystems here. According to Birdlife Malta spokesman Nathaniel Attard, these ducks should not be allowed in natural areas:

Swan populations in other countries have had to be checked due to their environmental impact. Yet it is the Muscovy duck which poses the greater threat to local ecosystems here

“Many ponds and valleys have been taken over by the Muscovy Duck. Both the Wild Birds Regulation Unit and the environment authority should treat this issue with urgency, along with other invasive alien species we find in our limited countryside. This should go along with a nationwide education campaign. They need to be monitored and controlled as they can damage the ecosystem.”

The organisation has participated in training sessions for Administrative Law Enforcement personnel on how to approach injured wild animals, including potentially dangerous birds such as swans. Ideally a Wildlife Crime Unit within the police needs to be set up and efforts should be made to have an ALE section operating in Gozo.

Mute swans were introduced from Europe to North America in the mid-1800s to embellish city parks and large estates. Many escaped to the wild and multiplied to the point where other species were being edged out.

A recovery programme for the threatened native Trumpeter swan led to removal of non-native Mute swan eggs by Michigan’s department of natural resources. Wildlife biologists are concerned over diving feeders such as the Scaup and Canvasback duck. They depend on particular aquatic plants which Mute swans consume in great quantities, tearing up more than they need. The target is to reduce Michigan’s mute swan population to less than 2000 by 2030.

Gozo-based ornithologist Joe Sultana points out that the Mute Swan is a rare vagrant to the Mediterranean and not a migratory bird in the true sense of the word.

“Only those breeding in the north east of Europe move out to winter in Mediterranean countries. Those which breed in the north-western European countries are found there all year round and are not migratory.”

“The Maltese islands do not offer adequate natural habitat to this species and its introduction to our islands would be wrong as it would be considered as an alien species. Introduction of such species would be harmful to our natural ecosystem. Vagrancy in migratory and non-migratory species is a natural phenomenon, usually occurring due to abnormal climatic conditions.”

Recognisable by its orange bill, the Mute swan’s call is more like a puppy barking, or a high-pitched whistle. Relatively silent, the few sounds they utter are audible a short distance away.

In contrast, the pounding of the air to lift such a large bird is audible over long distances. Sound recordings of the Mute swan’s wing beat can be heard on the xenocanto.org website. They can weigh up to 13kg with a wingspan of over two metres.

www.xeno-canto.org/species/Cygnus-olor?dir=1&order=typ

A feral population of Muscovy ducks can often be seen swimming in Ta’ Żieta Valley reservoir, l/o Victoria, in winter. This duck species is reported to be an omnivore with a taste for lizards, mice and small birds.A feral population of Muscovy ducks can often be seen swimming in Ta’ Żieta Valley reservoir, l/o Victoria, in winter. This duck species is reported to be an omnivore with a taste for lizards, mice and small birds.

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