Paper Reviewed
Miles, W.T.S., Bolton, M., Davis, P., Dennis, R., Broad, R., Robertson, I., Riddiford, N.J., Harvey, P.V., Riddington, R., Shaw, D.N., Parnaby, D. and Reid, J.M. 2017. Quantifying full phenological event distributions reveals simultaneous advances, temporal stability and delays in spring and autumn migration timing in long-distance migratory birds. Global Change Biology 23: 1400-1414..

In describing their study and reporting its findings, the twelve United Kingdom researchers say they "used 60 years (1955-2014) of daily bird migration census data from Fair Isle, Scotland, to comprehensively quantify the degree to which the full distributions of spring and autumn migration timing of 13 species of long-distance migratory birds changed across a period of substantial climatic and environmental change." And what did they learn by so doing?

Miles et al. write that (1) "in most species, mean spring and autumn migration dates changed little," but that (2) "the early migration phase commonly got earlier, while [3] the late migration phase commonly got later," so that (4) "species total migration durations typically lengthened across years."

Last of all, therefore, Miles et al. warn us that (5) "using only one or two metrics should consequently be interpreted cautiously because divergent changes occurring simultaneously could potentially have remained undetected."