The species is non-migratory and characterised by female-only parental care and high adult survival. On Laysan, long-term pair bonds are common, and 3-4 eggs are laid per clutch. The timing of breeding varies significantly between years, with the beginning of incubation varying from December to July (Reynolds et al. 2007). It selects different habitats during different times of the day. Most adult birds use dense cover and hide in the terrestrial vegetation during the day. During the evening and at night (Reynolds 2004), the species uses the central hyper-saline lake on Laysan, but concentrates near freshwater seeps around the shore (M. Morin in litt. 1999), especially when raising young ducklings which are less tolerant of hyper-saline conditions. It nests and rests in dense stands of shrubs and grasses (Moulton and Marshall 1996). It feeds principally on invertebrates, but also grass and sedge seeds, and some algae (Reynolds et al. 2006a); brine fly Scatella sexnotata is an important prey species whose peak spring abundance is positively correlated with annual brood production of the teal (Reynolds et al. 2007). Reintroduced birds on Midway Atoll appear to breed successfully at an earlier age and produce larger clutches than birds on Laysan, probably owing to more food and a low population density. On Midway, individuals in their first year and produce an average clutch of seven eggs, whereas birds on Laysan nest in their second year, producing an average of 3.3 eggs (Walters and Reynolds 2013). Duckling survival is low on both sites.

The species is endemic to the Hawaiian Islands (U.S.A.), where it became confined to Laysan Island. The birds do not disperse from Laysan today, but sub-fossil remains indicate that it was widespread on the Hawaiian Islands in the past (Reynolds and Kozar 2000), most recently being extirpated from Lisianski Island about 150 years ago. The species was near extinction at the beginning of the 20th century, but the population increased to 500 individuals in 1987 (Marshall 1992), following the removal of introduced rabbits from Laysan. In 1993, there was a complete breeding failure and severe die-off owing to drought and disease. Poor monitoring at this time impairs accurate population estimates, but post-hoc analysis suggests that the population dropped to 82-127 adults from a peak of 743 birds prior to the drought. Since then, the population gradually increased, reaching an estimated 521 birds in 2010 (M. Reynolds in litt. 2011).
Apparent population fluctuations over the past century were previously attributed to differing methods and seasons of counts (Marshall 1992), but are now thought to relate to genuine changes (M. Reynolds and G. Ritchotte in litt. 2002). With the Laysan population possibly approaching carrying capacity, 42 individuals were translocated to the two islands of Midway Atoll National Wildlife Refuge in 2004 and 2005; the birds bred successfully in their first year (Reynolds and Klaviter 2006). The founder population increased in size to a total of 104 individuals in 2006 (Jarrett 2006), reaching c.200 adult and juvenile (post-fledging) individuals by the end of 2007 (USGS unpublished data, Reynolds et al. 2008) and predicted to grow to a total of 380 birds (Reynolds et al. 2008). Although being hit by an outbreak of avian botulism in 2008 which killed over 160 birds (a decline of up to 40-50%) (M. Reynolds in litt. 2008), the preliminary estimates from Midway placed the population in 2010 at c. 350 (M. Reynolds in litt. 2010).
The Laysan population is believed to have been reduced by 50% following a tsunami in March 2011 (J. R. Walters in litt. 2013). On Midway, approximately 20-30% of the banded adult birds observed before this tsunami were not observed afterwards (M. Reynolds in litt. 2012). In 2014, 28 individuals were translocated from Midway Atoll to Kure Atoll, a mammalian predator-free island which lies approximately 1,350 miles north-west of Honolulu (Ward and Fredrickson 2014). As of early May 2015, 19 ducklings had hatched on the island (Anon. 2015). 

Conservation Actions Underway
CITES Appendix I. Laysan is part of the Hawaiian Islands National Wildlife Refuge. The alien grass Cenchrus echinatus is thought to have been eradicated (M. Morin in litt. 1999) and native bunch grass has responded positively (Reynolds et al. 2006b). Snow fences were installed 20 years ago to reduce the movement of sand and support natural revegetation (Moulton and Marshall 1996). A comprehensive restoration plan for Laysan Island has been developed, some sections of which are underway (U.S. Fish and Wildlife Service 2009). In 2004-2005, 42 wild birds translocated from Laysan Island were released on Midway Atoll and many bred successfully in their first season. Management on Midway Atoll includes monitoring the ecology and demography of the species as well as the enhancement and creation of freshwater wetland habitats (VanderWerf 2012). Following the success of the releases on Midway, the next translocations were discussed for Kure or Lisianski Islands in the north-west Hawaiian Islands (USGS unpublished data, M. Reynolds in litt. 2008) and in 2014, Kure Atoll received 28 individuals from Midway Atoll (Ward and Fredrickson 2014). During the 2008 avian botulism outbreak on Midway, 28 sick birds were successfully treated with anti-toxin, rehabilitated and released, and the rapid removal of sick and dead birds was thought to have prevented the impact of the outbreak becoming even worse (M. Reynolds in litt. 2008). Management strategies have been initiated on Midway Atoll that should reduce the future impact of avian botulism outbreaks, including: annual flooding of the concrete-lined catchment during the summer months; drainage and cleaning of the catchment in the autumn or winter months to remove accumulated debris and seabird remains; vegetation removal around wetlands to allow carcass detection; weekly population monitoring that includes carcass removal and searches for sick birds; wetland carcass searches daily during the summer months; and use of heavy equipment and portable pumps each year to improve water quality (Work et al. 2010). 

Conservation Actions Proposed
Continue to monitor the population size and health on Midway Atoll, Laysan Island and Kure Atoll. Continue to enhance nesting habitat on Midway by planting native bunch grasses. Remove mice (Mus musculus) from Sand Island, Midway, to allow recruitment of native bunch grass (VanderWerf 2012). Enhance brood-rearing habitat on Midway Atoll with small fish-free freshwater wetlands with abundant cover. Use translocation and ecosystem restoration to re-establish three additional populations of Laysan Ducks. On Laysan, continue to stabilise dunes by planting native vegetation (Moulton and Marshall 1996) and remove alien plant species (VanderWerf 2012). Restore freshwater wetlands on Lisianski prior to potential re-introduction. Ensure strict procedures to prevent the accidental introduction of exotic plants, invertebrates and animals (Moulton and Marshall 1996). Control exotic plants likely to negatively impact the species. Conduct further alien predator eradications to create potential for reintroduction to other larger, higher elevated islands. After restored predator-free habitat is available, create a new genetically managed captive population within Hawaii to provide birds for reintroductions to other Hawaiian islands (Reynolds et al. 2006b). Assess genetic variability of translocated populations for several generations post-translocation, and introduce new individuals where necessary to maintain genetic variation in the population (Lavretsky et al. 2014). Investigate the feasibility of vaccinating at least some birds in the Midway Atoll population against avian botulism (Work et al. 2010). Investigate the driving forces behind differences in fecundity, clutch size and population fluctuations between birds on Midway and Laysan (VanderWerf 2012).