The value of urban green spaces as important habitats for the maintenance of diverse wildlife species is not well explored in the Philippines. Data on bird diversity in urban areas like Davao City is very scant. Thus, the study documented bird species diversity in 15 urban green spaces of Davao City. These areas were previously not surveyed based on published literature. This study is also the first attempt to determine the correlation between green space size and Shannon diversity values. Green spaces were pre-selected, and bird censuses following a zigzag walk across each green space were conducted from October–December 2019. Coordinates of surveyed areas plotted on a digital map were used to estimate green space size. Diversity values were calculated using Shannon and Simpson indices. Pearson r correlation was employed to calculate the correlation between green space size and Shannon diversity values. Fifty-three (53) species (32 families) were accounted for, with 28 species added to the current list of birds from Davao City’s urban green spaces. Endemism was relatively low across all sites (17%). Only four species were common in all sites – namely, Passer montanus, Lanius cristatus, Cinnyris jugularis, and Pycnonotus goiavier. Shannon diversity values varied across sites (highest H' = 3.128, lowest H' = 1.688) and showed a positive correlation (r = 0.54) with green space size. Despite positive correlation, larger green spaces do not necessarily have the highest Shannon diversity values, suggesting that bird diversity in urban green spaces may be influenced by other factors. This warrants verification in the future to include studies on green space vegetation and complexity, noise level, and impact of anthropogenic activities.