After flying into a window in Victoria, the capital of British Columbia, the hawk was taken to a nearby wildlife facility where staff noticed a number of ticks near the bird’s eye. As per protocol for veterinarians in the province, the ticks were collected (all 22) and sent for testing in Ontario. Four of the ticks tested positive for Borrelia burgdorferi, the bacteria that causes Lyme disease.
Hawks as Lyme Disease Host
Worryingly, some of the ticks on the raptor were still in their larval stage, suggesting that they actually became infected with the bacteria from the bird itself. This means that the hawk is a reservoir host, maintaining the infection and transmitting it to ticks that go on to feed on the birds’ blood. These ticks may then drop off and feed on another mammal, spreading the infection.
Fortunately, the ticks found on the hawk were Ixodes auritulus, a species not known to bite humans. They can, however, bite other animals that other species of ticks later feed on before biting humans, thus spreading the disease indirectly. Due to the mobility of these birds, the discovery that they are a reservoir for Lyme disease is worrying as they may pick up infected ticks in one province and then drop them in another.
BC health officials have only recently begun to recognise the presence of Lyme disease in the province and while songbirds have often been found to carry Lyme-positive ticks, this is a first for the bird of prey population, of which there are many on Vancouver Island and the Gulf Islands. Eagle-watching tours might have an added element of surprise now it seems.