Cat causes carnage in rare seabird colony
Claire Greenwell, a doctoral student at Murdoch University's Harry Butler Institute, helped establish the fairy tern colony in Mandurah, southwest Australia, which gave birth to a flourishing colony containing 111 nests at the end of November 2018.
But following the observation and photography of a white cat in the colony, the carcasses of six decapitated adult terns were found and at least 40 chicks were found missing, wounded or dead in a few days. By mid-December, the 111 nests in the colony had been abandoned and the remaining seven chicks fed by adults were finally taken by a kestrel.
Ms. Greenwell was observing the colony for her doctorate and said that this unfortunate carnage illustrated how important the management of free-range cats was to the protection of wildlife.
"Cats are wonderful pets, but owning one has responsibilities. This means providing them with a safe and secure environment, which helps to protect them from damage and reduce their impact on wildlife," said Ms. Greenwell.
"Fairy terns nest in colonies on the shore, near where their main prey, baitfish, are abundant. But these areas make them vulnerable during the nesting season, especially to human impacts such as coastal development and intensive shoreline use, to the point that many former colonial sites are no longer suitable for birds.
"These impacts, combined with predation by wildlife species such as foxes and cats, have resulted in a 24% decline in the population in eastern Australia in just 30 years."
Ms. Greenwell said that the cat suspected of being responsible for the death was captured by the city of Mandurah and treated under the Cat Act WA (2011). The cat had been desexed but was not equipped with a collar or microchip.
This study clearly shows that the reactions of semi-ferrestrial cat populations to the release of neutral traps would not be sufficient to prevent them from hunting native species, she said.
New law on cats
In response to the death of terns and the abandonment of the colony, the city of Mandurah adopted a new local cat law implementing cat-free zones, cat fences around a wetland important to migratory shorebirds and various cat control measures.
Ms. Greenwell said the community's passion for the Mandurah Fairy Tern project played an important role in establishing the new cat law.
"It is great to see the adoption of these new laws, which will have important implications for a wide range of species in the region," said Ms. Greenwell.
"This is an excellent example of how community engagement can foster stewardship, but also the opportunity to change policy and management in response to issues of importance to the community.
