Annual survival estimates and risk of fluoroacetate (1080) secondary poisoning for New Zealand falcons (Falco novaeseelandiae) in a managed exotic forest

Abstract

Context The risk of secondary poisoning to native fauna during pest control operations is an issue of global concern. In New Zealand, non-target impacts during sodium fluoroacetate (1080) operations are particularly contentious. 1080 is used extensively for pest control for conservation, bovine tuberculosis control, and in plantation forestry for seedling protection from herbivores. The endemic New Zealand falcon (Falco novaeseelandiae) breeds in Kaingaroa forest, an intensively managed pine plantation where regular 1080 poison operations are conducted; however, causes of mortality and risks of secondary poisoning by 1080 are not well documented. Aims We aimed to investigate mortality and survival of adult falcons with an emphasis on assessing the possible role of 1080 poisoning in annual mortality. Methods Using radio-telemetry and visual observations, we monitored 37 marked adult falcons before and after 1080 operations in 2013–14 (16 through carrot-bait and 21 through cereal-bait operations) and assessed mortality causes through post-mortem examinations. Using Program MARK, the annual survival rates for adults and independent juveniles were estimated from long-term banding data (2003–2014). Key results Survival of falcons was high through both cereal-bait (21/21) and carrot-bait (15/16) 1080 operations (overall 95% CI for survival = 84–100%). The exception was a radio-tagged male that died of unknown causes within a fortnight of an operation and tested negative for 1080 residues. Three falcons were depredated by introduced mammals. One falcon was found dead in an emaciated condition but evidently died from head injury through Australasian magpie (Cracticus tibicen) attack. The annual survival rate of falcons estimated from long-term banding was 80 ± 6.0% (mean ± s.e.) for adults and 29 ± 0.1% for juveniles. Conclusions No adult falcon death was attributable to 1080 poisoning in this study. Identifiable mortalities were attributable to depredation by introduced mammals and an injury from an Australasian magpie. The annual survival rate of Kaingaroa falcons was comparable to those of other raptor species worldwide. Implications The risk to adult falcons from 1080 secondary poisoning is likely low. Whether this is also true for juveniles requires further study.

Dispersal and Survival of Red-Shouldered Hawks Banded in Suburban Southern Ohio, 1996–20181

“…Survival, not reproductive rate, is the most significant factor affecting lifetime reproductive success among long-lived birds such as raptors (Newton 1989). Survival varies by age class, with young raptors typically having lower annual survival rates than older ones (Lieske et al 2000, Serrano and Tella 2012, Faccio et al 2013, Horikoshi et al 2018, and can also vary with dispersal distance (Bloom et al 2011, Serrano andTella 2012), and sex (Jonker et al 2014, Colchero et al 2017, Reynolds et al 2017. Urbanization also might be expected to affect raptor survival due to numerous anthropogenic threats including collisions with vehicles and buildings, electrocution, and poisonings (Hager 2009).…”

Methods in amphibian biotelemetry: Two decades in review

“…Early examples of biotelemetry equipment were often designed and constructed by researchers for their own use (Tester 1963;Lonsdale & Baxter 1968;de Castro & Brower 1977;Taylor & Lloyd 1978) but, since 1965, commercially manufactured systems for biotelemetry have become more readily available (Kephart 1980;Senkowsky 2003). With wide availability and ever-decreasing costs, biotelemetry has been used in studies on mammals (O'Donoghue et al 1998;Kolowski & Holekamp 2006;Hamilton et al 2017Hamilton et al , 2019, birds (Naef-Daenzer et al 2001;Yoder et al 2004;Klaassen et al 2014;Horikoshi et al 2018;Muller et al 2019), fish (Jepsen et al 1998;Lennox et al 2017), reptiles (Scott et al 2014;Laarman et al 2018;Wolfe et al 2018) and even insects (Hedin et al 2008;Wikelski et al 2010;Hagen et al 2011). However, despite the continual advancement of technology, amphibians remain a challenging taxon for biotelemetry use.…”

Designing Timber Harvesting to Enhance New Zealand Falcon Populations

“…To apply this concept to assess habitat quality, it is necessary to measure the survival and reproductive rate of the species to determine that the habitat does not act as sink and can support a self‐sustaining population of that species in the absence of immigration (van Horne 1983, Pulliam 1988); otherwise, population density may be a misleading indicator of habitat quality (van Horne 1983). Based on long‐term band recovery data (2003–2014), the adult survival rate of the falcon population in Kaingaroa Forest was 80 ± 6.0% (SE) and for first‐year juveniles was 29 ± 5.0% (including emigration) with re‐sighting rates of females of 61 ± 5.0% and males of 44 ± 5.0% (Horikoshi et al 2018). The clutch size is 2.8 ± 0.7 (SD) with 73% reproductive success when ≥1 chick fledged (Horikoshi 2017).…”