Below is an excerpt from Kate Whittington’s post on Eyes on Environment about the dangers of captive breeding. Click here to read the entire post!
When a species faces imminent extinction captive breeding is often the go-to method to ensure the preservation and bolstering of wild populations. Not only does this aid the recovery of the population, producing more individuals for release whilst other in-situ conservation efforts are underway , but it also acts as a potential safety net should the wild population be wiped out. This seems like a sensible precaution, but is captive breeding always the best option? For the critically endangered great Indian bustard – perhaps not.
The value of captive breeding programmes depends on the ability to re-establish a population in the wild. While there are many success stories, it can be a challenging and unpredictable process – the difficulty of getting giant pandas to breed is a prime example (it took eight years before a single cub was born).
Standing a metre high and weighing nearly 15kg the great Indian bustard is one of the largest bird species in the world, making it a prime hunting target in the past for both food and sport3. While this initiated its decline, current threats stem mostly from habitat loss and degradation due to agricultural expansion, infrastructural development such as road networks and electricity pylons, as well as mining and industrialisation1. As a result the species has undergone severe population declines, from over 1,000 in 19701 to around 250 or fewer individuals today3.
In a recent study a team of scientists from the University of East Anglia, in partnership with Birdlife International, used population models to evaluate the potential effectiveness of a range of captive breeding and release programmes for the great Indian bustard, compared with wild (in-situ) conservation.
Given the already depleted wild population, any collection of bustard eggs for captive breeding would need to have a strong chance of survival and reintroduction to make an ex-situ conservation programme worthwhile. So the key question is whether the benefits from releases of captive bred animals outweigh the loss of wild individuals captured to begin captive breeding. First and foremost then, you need to be able to breed plenty of birds and be confident that they will reproduce as well as their wild counterparts.
Unfortunately bustards are particularly difficult to keep and breed in captivity. Described by the scientists as a “challenging stress-and-injury prone species”, large bustards are particularly susceptible to accidents and fractures in captivity, as well as having delayed reproductive maturity and low fecundity2. This would be on top of more general risks associated with captive breeding, such as loss of genetic diversity, domestication (via the passing down of traits which would be disadvantageous in the wild), failure to reach self-sustaining levels, and poor survival rates following reintroduction2.
Read the rest at Eyes on Environment!
- BirdLife International. Species factsheet: Ardeotis nigriceps (2015).
- Dolman, P. et al. “Ark or park: the need to predict relative effectiveness of ex situ and in situ conservation before attempting captive breeding“. Journal of Applied Ecology 52 pp.841-850 (2015).
- IUCN “Big birds lose out in a crowded world” June 7, 2011.