Does increased “Nesting success” mean birds are better off after poisoning?
* “Nesting success” is one of many factors affecting the size of a bird population
* It is likely to increase if a large part of a population is killed off
* Increases in nesting success after 1080 are short-lived
Effects of population density and supplemental food on reproduction in song sparrows
date | authors | source | name | quote |
2015 | NZ Journal of Ecology 39(2): 245-253 | Innes, J., King, C., Bartlam, S., Forrester, G., & Howitt, R. | Predator control improves nesting success in Waikato forest fragments | “Removal of ship rats and possums in December improved the 14-day probability of survival of artificial nests…In January, the 14-day probability of survival in all three blocks was intermediate…and the variation between them could not be explained by including pest control in the model…” |
2015 | NZ Journal of Ecology 39(2): 245-253 | Innes, J., King, C., Bartlam, S., Forrester, G., & Howitt, R. | Predator control improves nesting success in Waikato forest fragments | The estimated daily survival rate [of monitored nests] in managed areas was higher than in unmanaged areas in December 2008 (0.99) compared with 0.968″ |
2015 | NZ Journal of Ecology 39(2): 245-253 | Innes, J., King, C., Bartlam, S., Forrester, G., & Howitt, R. | Predator control improves nesting success in Waikato forest fragments | “even a large increase in nesting success does not in itself guarantee an increase in the population of the protected species” |
2014 | Schadewinkel, R., Senior, A., Wilson, D., Jamieson, I. | NZ J Ecol. 38: 315-321 | Effects on South Island robins (Petroica australis) from pest control using aerially applied poison | “We found no evidence that the reduction of rats and possums to below detection level increased robin nesting success” |
1999 | Prime, K., Nugent, G., & Innes, J. | Landcare Research He Kōrero Paihama Possum Research News – 11:May | Pigeons versus Possums: 7-0 at Motatau | “Sadly the decline in nesting success is very rapid with even small increases in possum and rat indices above this very low threshold, suggesting that, for these birds {kokako and native pigeon} pest control has to be done extremely well to have any benefit at all.” |
2013 | Environmental Protection Authority | Annual Report on the Aerial Use of 1080 for the year ended 31 December 2013 | “Monitoring of nesting success of rifleman, show that rifleman have dramatically higher nesting success immediately after aerial 1080 operations, with the effect lasting for at least a year…Robin nesting success also dramatically increases following an aerial 1080 operation. However, it has not yet been determined how long this effect lasts. DoC has yet to analyse nesting success of other species” | |
2011 | Eason, C., Miller, A., Ogilvie, S. & Fairweather, A. | NZ Journal of Ecology 35(1): 1-20 | An updated review of the toxicology and ecotoxicology of sodium fluoroacetate (1080) in relation to its use as a pest control tool in New Zealand | “during a 1080 carrot operation in 1997, mortality of tomtits (Petroica macrocephala) was estimated to be 79% (Powlesland et al. 2000). However, the tomtits had enhanced nesting success following the 1080 operation, with pairs rearing two, and in some cases, three broods the following season.” |
1979 | Spurr E.B. | NZ Journal of Ecology 2: 46:63 | A Theoretical Assessment of the Ability of Bird Species to Recover from an Imposed Reduction in Numbers, with Particular Reference to 1080 Poisoning | “Most females lay several eggs annually, so that adult recruitment in a stable population is much less than the reproductive output. The excess reproductive output can increase the population, especially when numbers are below the carrying capacity of the habitat.” |
1984 | Nilsson, S.G. | Ornis Scandinavica 15: 167-175 | The evolution of nest-site selection among hole-nesting birds: the importance of nest predation and competition | The proportion of Nuthatch nesting attempts that failed because of such interference {by starlings} was higher in high nests and when the population density of the Nuthatch was high” |
1988 | Arcese, P., Smith, J.M. | Journal of Animal Ecology 57:119-136 | “Several measures of reproductive success [in sparrows] declined as population density increased” |