- Nine years into a management package designed to support a recovery of wild red-legged partridge in Spain, scientists assessed its success.
- More than four times as many partridges were seen at counts of spring pairs, summer birds and autumn birds.
- Breeding productivity (number of chicks per pair) more than doubled in the first five years.
- Management for red-legs is affordable, feasible, and can help support wild red-leg recovery, with the potential for shootable populations within 4-5 years.
The red-legged partridge (red-leg) is a native species in Spain, but wild populations have dropped by a third in the last 15-20 years. This is for several reasons, including habitat loss, changes in farming practices, over-shooting and large-scale rear and release affecting wild populations.
A game management package had been introduced in 1995 to support wild red-leg recovery, which included habitat improvement, legal predator removal, supplementary feed and watering, and voluntary shooting restraint. Also, wild rabbits were managed to increase their densities, as they are a keystone species for the Mediterranean ecosystem. This study examined the impact of these measures on the local wild red-leg population.
What they did
The study was done in a large agricultural area in northwest Spain, a little over half of which (59%) is scrubland and forest, and the remainder is open arable fields. In 1995, there were around 2-3 spring pairs per square kilometre.
Birds were counted in spring (March), and it was noted whether birds were paired for breeding or not. Birds were also counted in summer (August), autumn (October) and winter (January).
As well as counting the birds and calculating density, throughout the course of the study, the scientists studied the survival of birds through summer and winter, their breeding success and productivity (see glossary).
What they found
Spring counts showed an increase of almost two pairs per square kilometre per year, with an overall increase from just under three pairs per square kilometre in 1995 to over 12 per square kilometre in 2006. Bird density increased in all season counts.
Summer survival rates stayed stable in the first six years of the project, and steadily increased through the second five years. The over-winter survival gradually reduced through the project.
Productivity rose through the study and was around twice as high by the end, compared to the baseline year at the beginning. Each breeding pair was producing twice as many chicks, but the proportion of pairs that hatched chicks remained stable at about half. Wild rabbit numbers also increased.
What does this mean?
Introducing a combination of habitat management, predator removal and shooting restraint increased the density of red-legs in the study area. There were more birds, and they were breeding better than at the beginning of the project. The financial calculations showed that the measures taken were economically viable, and that rabbit populations increased as well, as was the aim. The authors suggest that these measures can be taken where there are at least two spring pairs per square kilometre, rather than rearing and releasing birds.
These conclusions are in agreement with previous GWCT research into grey partridge recovery through targeted management, though more detailed studies should be done for red-legs.
Read the original abstract
Sánchez-García, C., Pérez, J.A., Díez, C., Alonso, M.E., Bartolomé, D.J., Prieto, R., Tizado, E.J., & Gaudioso, V.R. (2017). Does targeted management work for red-legged partridges Alectoris rufa? Twelve years of the 'Finca de Matallana' demonstration project. European Journal of Wildlife Research, 63:24: 1-5. DOI: 10.1007/s10344-017-1083-8.
- Breeding success: The proportion of nests that successfully hatch at least one chick.
- Density: The number of something in a given area. For example, if ten birds are in a one-acre wood, the density is ten birds per acre. If ten birds are in a ten-acre wood, the density is lower – one bird per acre, although the number of birds is the same.
- Habitat: The type of environment in which plants and animals live. The term includes the characteristics of the whole area, including plants, other animals, food supply, physical characteristics etc.
- Keystone species: A species that has a larger than expected effect on the environment in which it lives. These species play a critical role in maintaining the structure of the ecological community in the area – and can determine the types and numbers of other species present. Ecosystems can undergo a dramatic change if such a species is removed, even though it may have only made up a small part of the community.
- Productivity: The average number of young produced per pair (number of young counted in summer divided by the number of pairs counted in spring).
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