Oct 19, 2020
Chapter 9: Release
This protocol is a draft, published without a DOI.
- Kerri Wolter1
- 1VulPro
- VulPro
Protocol Citation: Kerri Wolter 2020. Chapter 9: Release. protocols.io https://protocols.io/view/chapter-9-release-bmjjk4kn
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: September 20, 2020
Last Modified: October 19, 2020
Protocol Integer ID: 42315
Keywords: vultures, vulture rehabilitation, vulture release, vultures after successful rehabilitation, vulture, rehabilitation, successful rehabilitation,
Abstract
This protocol describes when, where, and how to release vultures after successful rehabilitation.
Attachments
Guidelines
It is vitally important that individual birds undergo an assessment prior to release. Any bird being released should be as fit as possible. Releasing a bird with an infection is a serious failure, and allowing that released bird back into a colony situation carrying contagious pathogens or infections, to potentially infect other birds in the colony, would act against the original goal of rehabilitation: to boost the overall population health and foster healthy wild individuals.
When is the bird ready to be released?
Only birds meeting the following list of requirements will be fit for release:
- Symmetry of wings when standing (both at rest and when extended).
- Birds should show strong flight capabilities and be able to gain height in a suitably large flight enclosure.
- Normal body posture, co-ordination, reaction and body movements are all essential.
- The bird should be assessed in social situations, if possible. Normal feeding habits, including interaction with a group of other vultures at a carcass, is an important indicator of successful feeding within a colony. The age and species of vulture must be taken into account during this assessment.
- In the case of leg injuries, even a minor limp must be considered carefully. To be released and survive successfully, a vulture must be able to run, perch on a movable object such as the branch of a tree, and defend itself within a group situation.
- Fully functional binocular vision is essential to cope within a colony and interact with other vultures. Any individual with blindness in one eye, or impaired vision, should not be released.
Where should the bird be released?
Birds in your care have been compromised for a reason, and often this is the result of some conflict within their environment (power line collision, exposure to poison, etc.). While it may seem intuitive to release the bird at the same location it was found, this is not always in the best interests of the bird as there is a chance for re- injury. It is important to consider the release location carefully to balance finding an ecologically and socially appropriate location, while trying to avoid the initial cause of injury, all giving the individual the best possible chance of survival.
The following must be considered for every release, on a case-by-case basis.
- Weather – warm days with no or little cloud cover are ideal; the conditions when thermals will be available. Rain should not be forecast for the next 24 to 48 hours, in the case that the bird does not decide to immediately leave the release site.
- Time of day – release birds in the late to mid-morning, if possible. Vultures are heavy-bodied, with high wing loads (body mass to wing area ratio) and will generally struggle to fly high and find thermals in the late afternoon.
- Habitat – ideally the habitat should be suitable for the species and within the species’ normal foraging range. For example, tree nesting-species should be released in an area with plenty of trees for perching opportunities. Colonial cliff nesting species would ideally be released near a cliff roosting or breeding location. The bird may fly away immediately, but if it does not, you need to feel comfortable with the release location if the bird decides to remain in the area for a while.
- Human disturbance – birds should not be released within the immediate vicinity of dense human habitation. No power lines (dangerous or safe structures) should be present for 1 km surrounding the release location. This allows the bird plenty of distance to take off and gain height without risk of collision. No dangerous power line or wind farm structures should be present in the greater ( > 1 km ) release area. If you have concerns over the safety of various power line structures, contact VulPro (see contact details in the Introduction).
- Social considerations – Vultures are very social creatures and choose to seek out the company of other birds. If several vultures have been rehabilitated together, it is best to release them together. It may be worth keeping a vulture which is ready for release until the other is ready, but only if the extra time held in captivity is short (several days). If one vulture will be held more than several days, it should be released as soon as possible. If possible, release the bird where other vultures will be present (i.e. a vulture restaurant, colony). At the very least, the release location should be a place where vultures are known to fly overhead on a regular basis.
- Food availability – Do not release a bird in a region where you suspect poison to be used. Similarly, do not release a vulture in a location where you suspect lead ammunition is used and gut piles or meat is made available for foraging birds. Well-managed vulture restaurants provide ideal, safe locations for releases. This allows the released patient time to adjust to the surroundings and feed before leaving the site, if it so chooses.
When releasing a vulture, lower your body (see CHAPTER 1 for pictures), bringing the bird’s feet to ground level, slowly allowing the bird to stand.
Then release your grip on its entire body and neck at the same time, stepping away to give the bird some space. Be careful never to drop or throw the bird down, nor allow the bird to fall prior to lowering it gently to ground level.
When releasing the bird or placing it back inside the enclosure, remain still and allow the bird to walk or fly away from you, rather than panicking it, in which case it may take off, flying into stationary objects / fences.
Do not force the bird to move. Allow the bird time to recover but monitor it for any unusual behaviour that could be a sign of heat exhaustion or injury from handling. The bird will decide for itself what to do next; it might fly off, run or drink water. Never force the bird to move or fly after the handling. Simply monitor and interfere only as a last resort if the bird appears not to be fit for release.
Vultures, when given the opportunity, will time their take-off to coincide with a thermal or an increase in wind strength, making the take-off easier. Birds in general prefer to take-off against the wind. Consider these factors when choosing the release site and direction.
Release a bird from a crate at ground level, and not from an elevated site such as the back of a vehicle.
Do not pull a bird out by a wing or the tail or tilt a crate to encourage a bird to exit. Give the bird time to leave the crate of its own accord.