Urban Ecosystems (2025) 28:111 https://doi.org/10.1007/s11252-025-01727-1 avoid urban areas despite the presence of suitable habitats, sometimes due to the presence of invasive species (Grarock et al. 2014). However, urban environments can also sup- port various wild species that are able to utilize the limited resources available in human-modified habitats. Certain urban habitats, such as large parks (Nielsen et al. 2014) and small wetlands (Rawal et al. 2021), have been identified as supporting higher faunal biodiversity. In urban areas, where natural habitats are increasingly fragmented and human influence is pervasive, tree cavities, often referred to as “keystone vegetative structures,” pro- vide essential refuges for a wide variety of wildlife globally (Hohl et al. 2023). These cavities serve as nesting, roost- ing, and food storage spaces for birds, small mammals (such as bats), insects, and other invertebrates, playing a crucial role in sustaining urban biodiversity. By offering these criti- cal resources, tree cavities support thriving populations of Introduction Urbanization has been shown to exert numerous negative effects on biodiversity and natural ecosystems, including increased human infrastructure and habitat fragmentation (McKinney 2008; Hou et al. 2023). Many animal species, particularly those sensitive to human disturbance, may  Vijay Kumar Koli vijaykoli87@yahoo.in 1 Wildlife Research Laboratory, Department of Zoology, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan 313001, India 2 Rajasthan Forest Service (Retd.), 14-15, Chakri Amba Saket Colony, Rampura Chouraha, Jhadol Road, Post-Nai, Udaipur, Rajasthan 313004, India Abstract Tree cavities play a vital ecological role in urban areas by providing essential habitats and resources for a variety of ani- mal taxa, including cavity-nesting birds, mammals, and insects, thereby contributing to urban biodiversity and ecosystem functioning. While most studies on cavity availability focus on forest habitats, little is known about their presence in urban environments. In cities, reduced tree densities, the management of tree branches for public safety, and the limited pres- ence of tree-excavating species may all affect the availability of tree cavities. In this study, we asked three key questions: (1) What is the frequency of tree cavities across different habitats in Udaipur city, Rajasthan, India? (2) How are cavities distributed on trees species? (3) How do the characteristics of natural and excavated cavities differ across habitats? (4) What factors influence cavity availability? We surveyed 487 individual trees representing 69 species across five urban habitats, with the majority being native (62.31%). A total of 474 cavities were recorded in 260 tree individuals, predomi- nantly in temple areas (60.34%) and residential colonies (22.78%). Natural cavities (67.67%) were more common than excavated cavities (32.33%), with natural cavities mainly found on the main trunk, while excavated cavities were more frequently located on primary and secondary branches. The characteristics of cavity-bearing trees did not significantly dif- fer (P > 0.05) from control trees, nor did they vary significantly across habitats. While cavity heights varied slightly across habitats, this was not statistically significant (P > 0.05), and cavity height increased with tree size. Habitat was identified as a primary significant (P < 0.05) variable influenced cavity availability per site. Our research showed the potential of present trees in Indian small growing city particularly in temple areas and residential colonies, to enhance urban habitats and to promote the conservation of biodiversity including cavity nesters and excavators. Keywords Urban forests · Urban wildlife · Ecosystem services · Cavity availability · Tropical city Accepted: 9 April 2025 © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025 Tree cavity availability and distribution across habitats in Udaipur (Rajasthan), a small Indian City: implications for urban wildlife Vijay Kumar Koli 1  · Rakesh Kumar 1  · Kanishka Mehta 1  · Satish Kumar Sharma 2 1 3