Human activities including supplemental feeding substantially impact wildlife. In South Florida, wetland birds including American white ibis increasingly forage in urban habitats where people provide anthropogenic food directly (feeding birds in parks) and indirectly (e.g., landfills, dumpsters). Urban habitat use and food supplementation likely affect ibis health, and ibis presence at urban parks provides opportunities to educate people regarding how their behaviors affect wildlife and public health. We captured white ibis in South Florida urban habitats and assessed diet, stress, and immunity to better understand how supplemental feeding and urban habitat use impact health. We also administered surveys addressing public perceptions of birds and bird feeding to visitors at South Florida urban parks where public bird feeding is common. Stable isotope analysis revealed that urban ibis consumed more anthropogenic foods and less aquatic prey. Isotopic signatures were depleted in δ13C and δ15N with increased surrounding developed land cover, suggesting increased ibis consumption of bread in more developed habitats. Corticosterone was positively correlated with H:L ratios, but no stress parameters were correlated with immune function. Stress and immunity varied considerably overall; however, some birds exhibited immune and stress levels indicative of either adaptation or chronic stress. Some ibis may therefore benefit from urban habitats, while others experience increased stress and suppressed immunity with implications for altered pathogen infection. Park visitors regularly fed birds at home (27%) or parks (60%), and 31% fed birds on the day of the survey. Visitors who fed birds were more interested in birds but varied in their motivations for feeding. Most visitors would stop feeding if birds carry disease, and visitors were generally uncertain if bird feeding benefits birds, and what foods are appropriate. We must educate people with realistic information about disease risk while communicating that public health depends on maintenance of environmental and wildlife health. Improving interactions between urban residents and local wildlife requires obtaining public support for management, which may include improving features of urban areas that support wildlife (e.g., regulating bird feeding), or highlighting the importance of wild habitat conservation or restoration if urban areas increase risks and jeopardize success for wildlife.