Phylogeographical patterns and population dynamics are usually interpreted by environmental disturbances and geographic barriers of the past. However, sister species may exhibit disparate patterns of genetic structures and population dynamics due to their habitat preference and altitude segregation. In this study, we tested how species-specific altitude habitat affected phylogeographical patterns in two sister snowcock species, Tibetan (Tetraogallus tibetanus) and Himalayan Snowcocks (T. himalayensis).

A panel of seven microsatellite loci and a fragment of Mitochondrial DNA Control Region were used to investigate genetic structures and population dynamics in hope of revealing the underlying evolutionary processes through the identification of possible past demographic events.

Our results suggest that T. himalayensis showed a significant phylogeographical signal in mtDNA (F_ST = 0.66, p < 0.001) and microsatellite (F_ST = 0.11, p < 0.001) data and is stable during the glacial-interglacial cycles in the Pleistocene and followed demographic contraction until 0.003 million years (Mys) ago. The phylogeographical signal of T. tibetanus is lower than the level of genetic difference among populations in mtDNA (F_ST = 0.41, p < 0.001) and microsatellite (F_ST = 0.09, p < 0.001) data, likely benefiting from stable habitats over a long period of time. T. tibetanus has been experiencing expansion since 0.09 Mys ago. However, an abnormally haplotype H9 from T. himalayensis clustering with T. tibetanus was spotted.

Our results indicate that differences in habitat preference and altitude specialities were reflected in the genetic structure patterns and population dynamics of these two species. These dissimilarities in life history traits might have affected the dispersal and survival abilities of these two species differently during environmental fluctuations. The results of this study also enriched our knowledge on population differentiation and connectivity in high altitude mountain ecosystems.

The behavior of cranes reflects many of their survival strategies, but little has been known of the incubation strategies of cranes, in which both parents share incubation duties, in response to cold temperatures in alpine environments. The lack of information may restrict the effective conservation of the threatened Black-necked Crane (Grus nigricollis), a biparental bird nesting in high elevation wetlands.

We directly observed and used infrared video cameras from 2014 to 2015 to study the incubation behavior and quantitatively measured the frequency and details of egg turning behavior in the Black-necked Crane at the Yanchiwan National Nature Reserve in western Gansu Province, China.

At lower ambient temperatures in the morning, crane parents spent more time on the nest with less recess frequency and prolonged on-bout duration, while at higher temperatures around noon, the parents had more frequent recesses from incubation and shorter periods between nest exchanges. They adjusted the amount of time incubating by varying the recess frequency and the length of on-bout duration. Mean nest attendance and egg turning frequency of females were significantly higher than those of the males. The nest attendance and on-bout duration of females showed a significantly negative relationship with those of males. The two parents responded differently to the change of temperature. Females spent more time on the nest at lower morning temperatures, while males increased their time on the nest at higher temperatures after noon. Higher incubation recess frequency and egg turning frequency were observed at noon, probably because parents spent more time foraging, taking advantage of the lower egg cooling rate.

Both Black-necked Crane parents in the alpine environment adjusted their behavior in response to the thermal requirements of eggs and the weather conditions experienced. Our findings demonstrate that parents of this species incubated in different but complementary ways and efficiently enhanced egg care in a dynamic environment, so as to maximize benefits from the warm portion of the day and the intense solar radiation while minimizing the cost of rewarming eggs and the risks of cooling eggs.