Chroicocephalus ridibundus Transcriptome or Gene expression
This BioProject contains paired-end bulk whole-blood RNA-sequencing data and associated sample metadata from 40 free-living black-headed gulls (Chroicocephalus ridibundus) sampled at Haigeng Dam on Dianchi Lake, Kunming, Yunnan, China, during the 2025-2026 wintering season. Twenty birds were sampled on 14 November 2025 and 20 on 16 January 2026, 63 days later. No individual was sampled in both rounds. The two independent cross-sectional cohorts allow characterization of sampling-round-associated differences in whole-blood gene expression, including coordinated immune-associated transcriptional patterns, between the two dates at this wintering site. Individual food intake and other date-linked ecological or biological factors were neither experimentally assigned nor comprehensively measured; therefore, the dataset supports between-round associations but does not identify a causal effect of supplemental feeding or any other single driver. The data provide a resource for non-lethal molecular monitoring and comparative studies of migratory bird physiology.