Global climate change is increasing variances in natural system, and this was also evident in northern Bering Sea during a marine heat wave that intensified in 2016. Crested auklets (Aethia cristatella), colonial seabirds of Alaska and Siberia, nest at mega-colonies (10⁶) in the northern Bering Sea. The usual patterns of phenology and foraging were disrupted in 2016. Colony attendance of crested auklets was 35-50% lower in latter June 2016 at Little Diomede I., AK, compared to 2015. The pattern was similar for the least auklet (A. pusilla). The two species nests sympatrically in rock talus. Crested auklets specialize on large zooplankton such as euphausiids and copepods. However, their C/N stable isotope values spanned three times the range in 2016 compared to 2015. Red blood cells in 2015 had greater enrichment of δ¹³C (t _0.05(2)86 = 11.3, p < 0.001) and lower values of δ¹⁵N (t _0.05(2)78 = 11.4, p < 0.001). In 2016 crested auklets had a less specialized diet and apparently foraged at higher trophic levels. Eleven percent of the crested auklets captured in 2016 (n=82) had incomplete acquisition of bill pigment. According to a phenology study, bill pigmentation is completed by early May. The bill pigment includes a fluorochrome that may be derived from euphausiid prey, as well as pentacyclic triterpenoids, that must originate in phytoplankton. In 2016, the species-specific citrus-like odorant was less evident and ceased earlier. These deficiencies suggest physiological limitations related to diet. Like the crested auklet, least auklets exhibited a disrupted consumption pattern. Their growing primary feathers had lower δ¹³C values (t _0.05(2)21 = -4.06, p< 0.001) and higher δ¹⁵N (t _0.05(2)21 = 8.22, p< 0.001) in 2016. While the northern Bering Sea is highly variable, the sharp discordance in 2016 was more extreme and appears to be related to the direct or indirect effects of increased ocean heat.