Tick Related Disease in Cage and Aviary Birds
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How Does Disease Occur
Disease is seen most commonly in outside birds who occupy aviaries under, or close to, trees. So the likely scenario is that other wild birds infected with ticks (most commonly collared doves, swallows, or raptors), roost in the trees overhanging the aviary. If, by chance, the ticks have been on these birds for about a week, having become fully engorged, they will be ready to fall off. The ticks land on the ground and take cover about the floor of the aviary. They mind their own business, hoping not to be eaten, going about their daily routine for the whole of the next year.
Annual tick activity, (eg feeding and breeding), is absolutely dependent on weather conditions. This activity - which includes disease in birds - has occurred in any month (bar December and January), although the highest incidence is in August and September. A research project in the UK showed that tick disease seasons tend to last for only 7-10 days, across the whole country. However, 2006 was the worst year since the project commenced, with cases being recorded regularly for nearly 2 months. Was this pure chance, or was this yet another affect of the warming climate? When disease does occur, numbers of birds are simultaneously affected over much of the country.
Ticks may attempt to attach to any part of a bird, although they would be instantly groomed off everywhere the beak can get to, i.e. not the head and neck, so this is where ticks will be found. As soon as the tick has attached, it injects ‘anticoagulant’ under the bird’s skin, so that the surrounding blood does not clot, and the tick can suck it out. When a tick initially attaches, it would be very small, but as it fills with blood it gradually swells, eventually reaching some 4-6mm in length, appearing similar to a ‘grey coloured coffee bean’.
Affected birds may be seen looking poorly, with closing or swollen eyelids, or swelling about the face, but often they are just found dead. Any bird found suddenly dead in an aviary should be carefully studied. If you find an area of severe bruising (a big purple patch), around the face or neck, then this bird has died of tick related disease, despite the fact that a tick may not be present.
What are the clinical signs in birds affected by tick related disease?
- Haemorrhage around the face or neck
- Swollen eyelids, face or neck
- Sudden unexpected death
Is tick related disease infectious ‘bird to bird?’
Absolutely not, BUT, if one bird has been affected, you instantly know that you have ticks in your vicinity and that weather conditions are such that ticks are active, and that all other birds in the vicinity are at risk NOW. Any sick birds should be presented to an experienced avian vet as soon as possible.
I have put together a therapeutic protocol, which tends to be effective in infected birds. In the recent study, 50% of affected untreated birds die, many of whom were simply found dead, with no premonitory signs. However, overall, less than 20% of treated birds died, with none of the last eight treated birds dying.
What action should you take?
Check all your other birds, spraying them with recommended levels of a suitable and effective parasitic spray (see your avian vet for advice on safe and correct drugs and dose rates). Also, action should be taken to treat any ticks which might be active on the floor at that time (see your avian vet).
So I had ticks this year, how can I prevent them in future years?
Once ticks are in your vicinity, you should consider your birds to be at risk in future years. Suitable preventive action is essential.
- Remove any overhanging trees
- Keep birds in suspended cages, preferably with ground living birds living underneath them (eg poultry or quail). The latter will eat any ticks they find on the ground. It is interesting that in regions where free range poultry has been banned because of Avian Influenza risks, the incidence of tick related disease has increased dramatically in all species.
- You could spray the ground around your aviaries on a prophylactic basis annually, prior to the main risk season. Whilst this might be effective, I would caution keepers against this, for fear of causing collateral poisonings, perhaps even affecting your own birds.
- Birds that are at risk could be sprayed during the main risk period, on a monthly basis. This may well be sensible if you are aware that your birds are at risk, but this could conflict with breeding and rearing seasons.
So what makes infected birds die?
Sadly, this remains a mystery. In my project, infected birds and ticks were screened for commonly identified infectious diseases transmitted by ticks, i.e. Borrelia spp, Babesia spp, Bartonella spp and Ehrlichia spp. - all with negative results.
Can bird keepers help?
Yes please. If you live in the UK and find a live tick on any of your birds, please do the following:
Place the tick, still alive, in a suitable container, with air holes in the lid, with a 2” square of kitchen paper, which has been slightly dampened. Please mail this to: “Tick Project”, Great Western Exotic Vets, 10 Berkshire House, County Park Estate, Shrivenham Rd, Swindon, SN1 2NR. The tick will have just had a meal of blood and will not need to eat for a year – so please do not worry that you are being unkind.
