The Blue-throated Hillstar Oreotrochilus cyanolaemus is a recently described hummingbird endemic to the southern Andes of Ecuador. This “Critically Endangered” species faces multiple conservation problems; thus, acquiring basic ecological information is a key step for guiding sound and integral conservation actions. We performed a series of expeditions throughout the cordillera Chilla-Tioloma-Fierro Urco to gain new data about its ecology, abundance, breeding, and distribution. From November 2019 to March 2020, we surveyed a total of 161.6 km searching for O. cyanolaemus, and gathered data on encounter rates, microhabitats used, and flower resources used. From November 2020 to January 2021 we studied the breeding ecology of the species. Occurrence records of O. cyanolaemus were used to build a species distribution model, based on climatic variables and the normalised difference vegetation index (NDVI). We found that the species is relatively more abundant in the western and central portion of its distribution range. Males were found using more shrubby habitats than females, who used more open habitats. They visited flowers of 11 plant species, with Chuquiraga jussieui and Puya ssp. being the most frequently used flowers. Nests were found in caves and rocky walls, and only one out of three active nests was successful. The distribution model indicated that the species has a potential distribution range of 62.7 km2. This manuscript is the first comprehensive evaluation of the ecological requirements of the species, and the information provided has important potential for use as a conservation guide for the species and its habitats.

Identifying the fate of birds’ nests and the causes of breeding failure is often crucial for the development of conservation strategies for threatened species. However, collecting these data by repeatedly visiting nests might itself contribute to nest failure or bias. To solve this dilemma, automatic cameras have increasingly been used as a time-efficient means for nest monitoring. Here, we consider whether the use of cameras itself may influence hatching success of nests of the Black-tailed Godwit Limosa limosa at two long-term study sites in northern Germany. Annually between 2013 and 2019, cameras were used to monitor godwit nests. In 2014 and 2019, nests were randomly equipped with cameras or not, and nest survival checked independently of the cameras. Nest-survival models indicated that survival probabilities varied between years, sites and with time of the season, but were unaffected by the presence of cameras. Even though predation is the main cause of hatching failure in our study system, we conclude that predators did not learn to associate cameras with food either when the cameras were initially installed or after they had been used for several years. Cameras were thus an effective and non-deleterious tool to collect data for conservation in this case. As other bird species may react differently to cameras at their nests, and as other sets of predators may differ in their ability to associate cameras with food, the effect of cameras on breeding success should be carefully monitored when they are used in a new study system.

An alternative to the cold-climate model for the evolution of viviparity is that the impetus for the initial transition from oviparity to viviparity is not an increase in the duration of egg retention but a shift in the location of nests to more superficial and thus warmer locations in the soil profile as temperature declines with increasing altitude or latitude. Shallower nest placement, however, would lead to increased egg mortality as a result of physiological stress or predation, and enhanced egg mortality would thus provide the initial benefit of extended egg retention. To test this hypothesis, I examined the thermal biology of three species of Sceloporus lizards living at high altitudes: S. virgatus (1800 m), S. aeneus (2800 m), and S. bicanthalis (3200 m). The oviparous S. virgatus and S. aeneus females laid eggs at depths of 6 and 2 cm, and mean body/nest temperatures were 24.6/25.2 °C and 19.9/20.8 °C, respectively. Because the initial increment in the duration of egg retention is presumably short, females of these oviparous species cannot initially keep their eggs appreciably warmer than they would be in nests. In contrast, mean temperatures of simulated nests (17.6 °C) of the viviparous S. bicanthalis were similar to the 17 °C low temperature threshold for development, and temperatures in some nests fell below freezing at night and rose to lethal levels during the day. Mean body temperatures of S. bicanthalis females were 20.1 °C; eggs retained during the entire developmental period would hatch 17 days sooner than they would if laid in a nest. Extended egg retention at the highest elevation site would thus provide two benefits: reduced mortality of eggs and accelerated development relative to that in a nest. These benefits, however, accrue because of the initial shift of nests from deeper to more superficial depths in the soil profile.