Species mean elevational range size pattern
Our study showed that the mean elevational range size pattern of breeding birds in Lebu Valley was a hump-shaped pattern. It is worth noting that there are several frequently used methods to describe species mean range size patterns. McCain (2013) used the “Steven’s method”, “midpoint method” and “quartile method” to explore the relationships of species mean range size and elevation for vertebrates from 160 mountains, and the results generated by these three methods vary greatly (McCain & Knight, 2013). For example, the result by using the Steven’s method showed that 40% of datasets found a positive relationship between species mean range size and elevation. However, only 0% and 38% of datasets found a positive relationship when using the midpoint method and the quartile method. Our study conducted three most commonly used methods to access the species mean elevational range size pattern, and all approaches yield a consistent hump-shaped pattern which indicated that our result was robust and unaffected by the measuring methods. However, to compare the results of different studies, we should use comparable methods to access the elevational range size pattern across regions or taxa.