Baseline semen characteristics of the Grey Partridge (Perdix perdix L.)

The grey partridge (Perdix perdix L.) is a monogamous member of the Phasianidae family that has experienced a significant population decline across Europe in recent decades. While previous studies have focused on semen characteristics in polygamous Phasianidae species, data on P. perdix remain lacking. This study aimed to provide the first comprehensive characterisation of semen traits in the grey partridge, establishing the reference values essential for further reproductive research. Semen was collected from ten adult males during the breeding season, and evaluated for ejaculate volume, sperm concentration, motility (including kinematic parameters), morphology, and morphometry. The mean ejaculate volume was 4.40 µL, with significant individual variation (P<0.05). Average sperm concentration was 1.64×10⁹ mL⁻¹, and total motility and progressive motility were 46.83% and 10.20%, respectively. Morphological assessment revealed that only 10.39% of live spermatozoa were morphologically normal, with bulb-head abnormalities being the most common (mean 27.20%). Sperm morphometry showed a relatively short midpiece (mean 1.77 µm) and total sperm length of 53.99 µm. Despite individual variability, the measured traits fall within the ranges reported for other small-bodied wild Phasianidae. The low proportion of morphologically normal sperm may represent species-specific patterns rather than abnormalities. These results provide essential baseline data for the grey partridge and support its potential inclusion in future assisted reproduction and conservation strategies.