Sula nebouxii raw RNAseq reads from blood, Sula nebouxii raw reads from the loci-specific PCR method (blood), and Fregata magnificens raw reads from the loci-specific PCR method (blood).

For RNAseq: We purified RNA from seven females and two males using the RNAeasy QIAGEN kit. We generated strand-specific RNA-seq libraries, using the Illumina TruSeq Stranded mRNA Library protocol. Each library was sequenced on Illumina HiSeq 2500 platform (101 nucleotides, paired-end). For the loci-specific PCR method: DNA samples were standardized to 10 ng/ul. We amplified the autosomal, Z-linked, and W-linked loci in the same PCR reaction using the Phusion Flash High Fidelity from Thermo Fisher Scientific (Cat. No. F548L). PCR products were purified using Agencourt AMPure XP (Cat. No. A63882). PCR products were multiplexed and sequenced in a NextSeq 500 Illumina machine (paired-end, 75 nucleotides long) at UNAM.