Addressing the harms of avian botulism

Avian botulism is a paralytic neuromuscular disease in birds that is often fatal if not treated. Birds become sick by ingesting invertebrates, such as maggots, that have themselves ingested toxins produced by the bacterium Clostridium botulinum. This bacterium thrives in shallow/stagnant waters where oxygen levels are low and nutrient levels are high.

There are multiple triggers for avian botulism outbreaks including: warming temperatures, rapid draw-down in water level, and large kill-off of fish in a waterway. Once the conditions are right for an increase in botulinum bacterium in the water, an outbreak occurs and persists in a cycle where birds and maggots continuously infect each other.

Avian botulism outbreaks are a naturally occurring event. Outbreaks can occur in human-created and managed waterways; therefore, we have an obligation to address this problem. In New Zealand, avian botulism outbreaks occur in canals, wastewater treatment ponds, stormwater treatment ponds, in addition to rivers and ponds, and shallow, brackish areas near the coast.

You can read more about our position on avian botulism here.

Birds that are sick from avian botulism experience several physical and mental harms related to the following:

• Inability to walk or fly. Their legs and feet are pushed back and wings hanging loose.
• Open mouth breathing.
• Inability to hold up their head.
• Other health issues can have similar symptoms, but the tell-tale sign for botulism is the delay or lack of a blinking response.
• Birds that are slow to fly away with their flock mates may also be in early stages of the disease.

Birds may experience fear and distress if they are feeling sick or disoriented, unable to escape threats, and around other birds in distress from the toxin.

All bird species can get botulism (except vultures). Mallards, shelducks, grey ducks, teal, shoveler ducks, geese, herons, terns, shags, and gulls are among the most common birds impacted by avian botulism.

Birds that are sick from avian botulism can be successfully treated, but this depends on quick action. Birds can be treated with fluids for rehydration, activated charcoal to absorb toxins, eye drops to protect their eyes from drying, and assisted feeding and supportive care. Once healthy, rehabilitated birds can be released back into the wild.

The longer the bird is sick, a successful recovery is less likely. In addition to feeling sick, the rehabilitation process also includes being captured in the field, held in a facility, and handled by people for treatment; all these things are stressful for a wild bird.

Botulism is a slow, painful, and stressful death. Sometimes, it is in the best interest for the welfare of the bird to be euthanased, instead of treating them for recovery. This happens when the bird is too sick that recovery is unlikely.

It is important that you take action when you find a bird that is sick or dead.

1. If you can safely and humanely capture the bird and immediately transport it to a veterinary hospital, SPCA Centre, or wildlife rescue:

• Prepare a box with holes for ventilation or use a pet carrier.
• The most common strain of botulinum bacterium that impacts birds is not a risk for humans; however, it is always best to take precautions. Wearing gloves, gently pick up the bird around the wings from behind and place in the box or carrier. Cover the bird with a towel or similar before attempting to handle them. This will make handling easier and the bird feel more secure.
• Keep the bird warm and calm during transportation. Place a sheet over the box and maintain a quiet atmosphere. If the bird cannot keep their head up, place a rolled towel in front of the bird’s chest and prop their head up on the towel.

• DO NOT feed or give water to the bird!

If you cannot safely and humanely move a sick bird:

2. Contact your local SPCA to alert them to a bird in distress.

3. Contact your local bird rehabilitation or rescue centre.

4. Contact the national hotline for the Department of Conservation (DOC) if the bird is native. Native and endemic birds that are sick or dead should be reported to DOC: 0800 DOC HOT (0800 362 468).

4. Contact your local Fish and Game ranger to report sick and dead birds. Fish and Game are actively involved in reducing the negative impacts of avian botulism.

5. Contact your regional or district council to report sick or dead birds on council land. This alerts them to locations where an outbreak is occurring and helps them understand the extent of the problem.

SPCA is concerned with the negative impacts of avian botulism on all birds. We are helping birds impacted by avian botulism in several ways:

• When we can, we respond to calls when a person reports a sick bird. We treat the bird and send them to an appropriate wildlife rehabilitation facility, when this is in the best interest of the bird.
• We partner with other organisations to strengthen communication between different agencies and organisations involved in an outbreak.
• We work with agencies and organisations to spread the word about the importance of changing human behaviour to reduce the negative impacts of avian botulism including:
• Encouraging people to not feed birds, especially, to not feed bread to birds. Bread ends up in the water, which can contribute to increasing nutrients and encouraging the growth of botulinum bacterium.
• Encouraging people to report birds that they find that are sick or dead as soon as they can. Reporting a botulism outbreak earlier allows earlier actions to end it or reduce the severity.
• Encouraging groups, such as councils, that manage human waterways to adopt best practices that reduce the likelihood and severity of avian botulism outbreaks.

SPCA is committed to minimising the harm that avian botulism causes to birds. We co-hosted a 1-day Avian Botulism Symposium in November 2019 which convened different agencies, organisations, and individuals involved in bird and water management. The goal of this event was to reduce the negative impacts of avian botulism on birds by strengthening relationships between water and bird professionals, driving innovation in bird and water management, and teaching hands-on skills for improved bird care, facility management, and public communication.

We continue to work with partners to advance better management of waterways to prevent outbreaks and help improve the humane treatment of birds and other wildlife who are impacted.