Urban bird commensals maintain coexistence under extreme food shortages

In developed cities, bird communities are typically comprised of a few dominant invasive species that can cause considerable social and economic costs. While various studies advocate restricting anthropogenic food as a suitable management approach, a significant knowledge gap persists regarding how these species interact and respond to such an intervention. Here, we evaluate if limiting a shared food resource may affect their abundances similarly and assess if such limitations influence their niche dynamics. In Singapore, open food centres for people, colloquially known as hawker centres, serve as key food sources for three highly adapted urban birds: feral pigeons, Javan mynas, and house crows. We counted these three species across 63 hawker centres and analysed their niche dynamics across different phases – before, during COVID-19 social restrictions when dining-in was prohibited, and during an enforcement phase mandating the return of crockery. We modelled their counts, diet niche wi..., A total of 63 hawker centres in Singapore were surveyed from 2019 to 2021. We conducted area searches and recorded the counts of feral pigeons, Javan mynas and house crows within the hawker centre premises and 10m of its perimeter (i.e., outside). To minimise double-counting, we only counted individuals that were detected in frontal view and omitted individuals that flew in from other sections of the hawker centre. The same surveyor conducted the surveys between different sampling occasions. We also observed their activity (i.e., feeding, perching and others which constitute moving either by flying, hopping or walking), perch location (i.e., ground, table, chair, elevated structures, tray return station and outside) and foraging substrate (i.e., ground, table, chair, crockery, tray return station and others). A tray return station is an open shelving unit for returning crockery, utensils and trays.
Predictors affecting bird commensal counts included food availability, structural attribu..., , ## Urban bird commensal maintain coexistence under extreme food shortages

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**Bird count data**
56 out of 63 hawker centres initially surveyed were used for bird count analysis
7 hawker centres were omitted to reduce autospatial correlation; all retained hawker centres are at least 400m apart

Occasion - period when the surveys were conducted: Before CB (Circuit Breaker), CB, P2HA (Phase 2 Heightened Alert), and Enforcement (i.e., after the enforcement of the tray return policy)
Hawker_centre - name of hawker centre
R.pig - rock dove or feral pigeon count
J.myn - Javan myna count
H.cro - house crow count
Stalls_open - number of hawker stalls opened at 1330 and 1500 divided by number of repeat surveys. In Before CB phase, the surveys were repeated twice at 1330 and same for 1500. Hence, Stalls_open = total stalls open / 4

*Next five variables below reflect the average values as described above for Stalls_open*
Feeding_incidences - number of bird feeding incidences within hawker cent...