Physiological and behavioral processes interact with environmental conditions to strongly influence organismal life history strategies which covary with latitude. However, few studies have articulated explicit linkages between metabolism and life history across latitudinal gradients. Interactions between metabolism and resource dynamics may give rise not only to patterns of variation in mean life history traits, but also to patterns in the ranges (diversity) of those traits across the same gradients. Here we show that the range of viable and realized metabolic/life history strategies covaries with the amplitude of seasonal resource fluctuations and, thus, latitude. Using a theoretical metabolic model we predicted that aseasonal environments support a greater diversity of life-history strategies than those subject to strong seasonality, where only 'fast' strategies were successful. We analyzed a global database of organismal metabolic parameters (estimated using a standard dynamic energy budget model) and found empirically derived evidence supporting our theoretical prediction that life history diversity negatively covaries with resource seasonality. These results comprise a novel framework for exploring covariation of life history with latitude at global scales, which may in turn help to explain other fundamental ecological patterns such as species diversity across gradients of seasonality.

Determining patterns in annual movements of animals is an important component of population ecology, particularly for migratory birds where migration timing and routes, and wintering habitats have key bearing on population dynamics. From 2009 to 2011, we used light‐level geolocators to document the migratory movements of Flammulated Owls (Psiloscops flammeolus). Four males departed from breeding areas in Colorado for fall migration between ≤5 and 21 October, arrived in wintering areas in Mexico between 11 October and 3 November, departed from wintering areas from ≤6 to 21 April, and returned to Colorado between 15 and 21 May. Core wintering areas for three males were located in the Trans‐Mexican Volcanic Belt Mountains in the states of Jalisco, Michoacán, and Puebla in central and east‐central Mexico, and the core area for the other male was in the Sierra Madre Oriental Mountains in Tamaulipas. The mean distance from breeding to wintering centroids was 2057 ± 128 km (SE). During fall migration, two males took a southeastern path to eastern Mexico, and two males took a path due south to central Mexico. In contrast, during spring migration, all four males traveled north from Mexico along the Sierra Madre Oriental Mountains to the Rio Grande Valley and north through New Mexico. The first stopovers in fall and last stopovers in spring were the longest in duration for all males and located 300–400 km from breeding areas. Final spring stopovers may have allowed male Flammulated Owls to fine tune the timing of their return to high‐elevation breeding areas where late snows are not uncommon. One male tracked in both years had similar migration routes, timing, and wintering areas each year. Core wintering and final stopover areas were located primarily in coniferous forests and woodlands, particularly pine‐oak forests, suggesting that these are important habitats for Flammulated Owls throughout their annual cycle.

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