Avian eggshell is a common component of many archaeological deposits, but its archaeological potential remains largely unexplored. The most obvious reasons are two-fold. Firstly, despite its abundance on many sites, eggshell is often overlooked during excavation. Even when it is recovered, small fragmented remains are difficult to identify taxonomically. Here we introduce a minimally destructive qualitative analytical technique for taxonomic identification of eggshell fragments based on highly sensitive mass spectrometry and peptide mass fingerprinting (ZooMS), and illustrate its application to eggshell recovered from the Viking Age urban site at Hungate, York. We adopt a more extreme version of the method of bleach treating used to prepare ancient eggshell for DNA analysis, followed by conventional peptide mass fingerprinting using MALDI-ToF mass spectrometry. The development of this technique will allow future research to make better use of eggshell fragments recovered from archaeological sites.