The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

Species conservation relies on determining the mechanisms that cause endangerment. This thesis documents the conservation ecology and phylogeography of an endangered lizard, Oligosoma grande, from southern New Zealand, and tests hypotheses that may explain its endangered status. Grand skinks are large rock-dwelling lizards endemic to montane grasslands in central Otago, New Zealand. They are classified as vulnerable to extinction by IUCN criteria and are the subject of intensive management. The causes of their endangerment are not well understood, but changes to landscape connectivity caused by agricultural development have been implicated. I developed microsatellite and mitochondria1 DNA markers, and combined them with field studies to address four key problems relevant to the conservation of this species. First, I investigated the ability of newly developed analytical tools for genetic data (assignment tests) to provide qualitative and quantitative dispersal information. I show that assignment tests can provide highly accurate dispersal information, and describe the circumstances where they perform best. Second, building on these results, I combined genetic and demographic data to provide an empirical account of how two forms of agricultural landuse affect the connectivity of skink populations. I show that the nature of the vegetation matrix between skink populations both quantitatively and qualitatively affected dispersal patterns, but also that characteristics of individual populations play a role in determining dispersal dynamics. Third, following the evidence that grand skink populations were very insular, I used parentage and kinship analysis to investigate the extent of inbreeding and inbreeding avoidance behaviours. It is often assumed that close inbreeding is harmful and animals should avoid it by either dispersing after birth, or recognising and avoiding mating with kin. However, I found no evidence for inbreeding avoidance or inbreeding depression. Finally, I used phylogeographic analyses to understand the contributions of historical and contemporary processes to O. grande's rarity and fragmented distribution. I demonstrate that that the current fragmented distribution has both historical as well as recent anthropogenic origins. Some populations show evidence of recent declines that may have occurred since human settlement in New Zealand, but in addition, more ancient biogeographic processes have driven population fragmentation.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

Nestling mortality in a reintroduced population of the endangered and endemic hihi/stitchbird (Notiomystis cincta) was investigated over one breeding season (2008-09) at Zealandia – Karori Sanctuary, New Zealand, to determine whether disease impacted on nestling survival. High rates of both hatching failure (56%) and nestling mortality (39%) in the first clutch made this the least successful breeding season since translocation in 2005. Overall 34% of eggs survived to fledge, compared to 52% and 58% in 2005-06 and 2006-07 respectively. Samples collected from 34 live and 25 dead nestlings were screened for evidence of disease. Bacterial and fungal pathogens were isolated from gastrointestinal swabs but there was no evidence of coccidia or other intestinal parasites in faecal samples. There was no evidence of significant abnormalities in the blood collected from hihi prior to fledging in the haematological parameters tested, and all blood samples were negative for malarial parasites. Tropical fowl mites (Ornithonyssus bursa) were found on nestlings and recovered from nest material in very small numbers. Sixty percent of nestling mortality occurred during the first 7 days of life, most often caused by starvation (16%) or poor pulmonary aeration (20%), and death was associated with seasonally low minimum daily temperatures below 11oC. Two older nestlings that died suffered from aspergillosis and an unidentified haemoparasite respectively. Seven nestlings (28%) aged 6-19 days died as a consequence of ventriculitis due to traumatic penetration by insect remnants identified as bee or wasp stings (Hymenoptera). The resulting granulomatous lesions were found in the gizzard mucosa, muscle layers and ventricular or intestinal serosa, and were associated with bacterial and/or yeast secondary infection. It was concluded that hihi may lack the evolutionary adaptations to safely consume introduced bees (Apis mellifera) and wasps (Vespula germanica, V. vulgaris) that are attracted to the feeding stations used to support reintroduced hihi populations. Histopathological examination showed candidiasis contributed to the deaths of four nestlings and Candida albicans was isolated from the gastrointestinal swabs of 13 live nestlings from four nest sites, eight of which survived to fledge. The potential of all pathogens may be increased by any cause of temporary or permanent immunosuppression and, in this establishing population, the majority of nestling deaths were associated with environmental conditions (temperature) and ecological factors (introduced prey). It is suggested that ongoing monitoring should include use of temperature data-loggers in hihi nest boxes, health screening of live nestlings, necropsy examination of dead birds, and spore counts to determine environmental levels of Aspergillus. Nest box insulation and/or heating could reduce the incidence of hypothermia in nestlings. A review of the carbohydrate provisioning protocols may reduce bee/wasp numbers and minimise the effect of Candida albicans at this site.

The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.