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Birds of prey

Aspergillosis

Aspergillosis is caused by a non-contagious infection with the fungus Aspergillus (Aspergillus fumigatus, most commonly). The disease is commonly seen in a number of species, including wildfowl, parrots and of course, birds of prey. This condition is probably noticed in birds of prey more acutely than in other birds due to the constant attention that these birds are under, in terms of daily weighing, and close monitoring of their performance when flying as well as on the glove.
Aspergillosis can manifest in five recognised forms (according to Dr Muller of the Abu Dhabi Falcon Hospital), and these are as follows:

  • New
  • Early
  • Advanced
  • Syringeal (lesions affecting the bird’s voicebox region)
  • Cutaneous

Early diagnosis via blood tests, radiographs and endoscopy is vital to aid the successful treatment of this condition. Treatment differs according to the advancement of the lesions, with oral antifungal treatment being required for up to 8 weeks.
In the UK, aspergillosis in birds of prey is most commonly recognised in a number of species, including the Snowy Owl (Bubo scandiacus), Northern Goshawk (Accipiter gentilis) and Gyr Falcon (Falco rusticolus). Birds appear particularly susceptible at times of stress, e.g. manning, undergoing transportation (especially with compromised ventilation during travel) or even whilst undergoing veterinary treatment for something unrelated. Straw has been shown to harbour an overwhelming amount of aspergillus spores, and as such should not be located anywhere within the proximity of your birds; whether in aviaries or out on whetherings. Because the infection may produce lesions at any number of sites within the bird, clinical signs may be vague and non-specific. The most common indication that a bird may be suffering with aspergillosis will be respiratory signs. This can be anything from increased effort and more rapid fatiguing during flying/hunting, to open-mouthed breathing with a heavy gular flutter (‘panting’) when at rest. The mutes (faeces) are often described as being a characteristic green colour in birds suffering from aspergillosis, but this is generally an indicated of liver disease; often seen secondary to systemic aspergillosis infection.
If you have any concerns about your bird being at risk from aspergillosis, do not hesitate to consult an avian vet about minimising the risk of your birds being exposed, as well as getting your birds checked for any early signs of the disease.

Bumblefoot

Pododermatitis, often referred to colloquially as ‘bumblefoot’ is a condition that is reported very commonly in captive birds, in comparison to the apparent rarity of the condition in their wild counterparts. A serious condition that can greatly affect a bird’s comfort and hunting ability, bumblefoot is a sadly common condition that is observed across the globe in both falconry and zoological collections.
The potential causes of bumblefoot are widely reported and debated, some of which include perch size, distance between perches, presence of astroturf on perches, diet, species, cleanliness within the aviary, etc. Each case of potential bumblefoot must be addressed on a case-by-case basis, with all merits and potential pitfalls of that bird’s routine scrutinised.
The most common bacterium found associated with bumblefoot on birds of prey is one that is surprisingly not usually found elsewhere on the birds, or in their mutes. This is Staphyloccocus aureus, which is interestingly found in large numbers on the human skin normally. Perhaps this indicates a need for the upkeep of rigorous hand hygiene before even considering handling birds for manning/jessing etc. It is also important to highlight that often many of the bacteria found when the birds feet are swabbed are those also found in the mutes, indicating the need to maintain a thorough cleaning regimen for the aviary and whethering perches and waterbaths.

Wing-tip Oedema

This is an inflammatory process that affects the most distal (furthest) aspect of the wing in birds of prey. Most often observed in young birds, it is most commonly observed over the winter months, where periods of frost overnight are most prolonged. It is usually seen in birds tethered close to the ground, or in those that have been lofted with wet plumage; either from flying or bathing.
The wing-tip oedema will manifest itself in cold swellings on the furthest edges of the wing, with a loss in performance of the bird when flown. Daily checks of the wings should be the norm, especially during the autumn-spring months of the year.
Affected birds may hold their wings in a drooped position, and any signs that a bird may be suffering from wing-tip oedema indicates an immediate need to see an avian vet.
Wing-tip oedema is a preventable condition, which if left untreated, may result in a young bird never being able to fly. Please take the necessary yet simple steps to ensure that your bird is not one of them.