Lead
On Feb. 4, 2023, volunteers and photographers in Phil Hardberger Park in San Antonio captured an unexpected interaction: a black vulture was photographed preening the head and neck of a crested caracara. The encounter, recorded by Bexar Audubon volunteer Lora Reynolds, drew local attention and prompted further reports from nearby observers. A separate sighting about a mile away the previous year, documented by Lori Boies, adds weight to the suggestion that such interspecific grooming may occur more often than the scientific record indicates. Experts say the behavior—known as interspecific allopreening—has been rarely documented but might be underreported in urban and suburban settings.
Key Takeaways
- On Feb. 4, 2023, in Phil Hardberger Park, San Antonio, a black vulture was filmed preening a crested caracara; the interaction was captured by volunteer Lora Reynolds.
- An earlier observation, roughly a mile from the park and described by Lori Boies, occurred in 2022 and lasted about 20 minutes with multiple vultures and caracaras involved.
- Both incidents were shared publicly via park and local nature accounts, prompting discussion among birders and ornithologists about frequency and function.
- Interspecific allopreening—grooming between different bird species—appears sparsely represented in academic literature despite repeated anecdotal reports.
- Possible functions include parasite removal, social tolerance, or opportunistic behavior in mixed-species roosts; none of these explanations are yet confirmed for these events.
- Observers noted the interactions occurred on perches and rooftops in urban-adjacent spaces, suggesting human-modified environments may increase encounter rates.
- Photographic evidence has been central to bringing these episodes to wider attention, underscoring the role of community scientists in documenting rare behaviors.
Background
Allopreening is a well-known behavior within single bird species, often serving hygiene and social-bonding roles. By contrast, grooming between birds of different species—termed interspecific allopreening—appears infrequently in the formal literature, which tends to focus on intra-species social dynamics. Urban and peri-urban habitats concentrate diverse species on limited perches and food sources, which can increase interspecific contact and potentially create opportunities for previously uncommon interactions.
In the region around San Antonio, both crested caracaras (a falcon-family raptor) and black vultures are regular, sometimes overlapping, users of open areas, roadsides and human structures. Caracaras and vultures differ markedly in foraging strategies and social systems, which makes the documented preening notable: it crosses taxonomic and ecological boundaries. Community scientists and park personnel increasingly upload images and notes to social channels, producing a new stream of observational data that researchers can mine for rare behaviors.
Main Event
On Feb. 4, 2023, a large raptor alighted in a tree at Phil Hardberger Park while a black vulture was already perched nearby; cameras captured the vulture actively preening the caracara’s head and neck. The encounter was seen and photographed by Lora Reynolds, a volunteer with the Bexar Audubon Society; those images were later posted by the park and shared on social media. Reynolds reported that, despite years of birding experience, she had not previously observed another species grooming a caracara.
Shortly after the park released the images, photographer and local scientist Lori Boies identified a similar episode from the prior year. Boies described first seeing two crested caracaras preening each other on a rooftop, then two black vultures joining and tending the caracaras’ heads, necks and chests for roughly 20 minutes. She initially took the scene as a photographic curiosity before checking scientific sources and recognizing the relative rarity of such cross-species grooming reports.
Both incidents were publicized through park and community channels rather than formal scientific outlets, which may explain why they were not previously documented in the research literature. The photographic record—rather than prolonged field observation—served as the primary evidence, enabling other birders and researchers to verify species identity and sequence of behaviors after the fact.
Analysis & Implications
The observations raise two linked questions: how often does interspecific allopreening actually occur, and what drives it when it does? One plausible proximate function is ectoparasite removal: preening addresses mites or ticks on vulnerable regions such as the head and neck. Vultures preening raptors could therefore represent hygienic behavior with immediate benefits for the recipient, while also providing a food or tactile stimulus for the groomer.
Another interpretation emphasizes social tolerance or habituation in human-modified landscapes. Where species aggregate around limited perches, food or thermally favorable structures, repeated proximity may reduce aggression and allow affiliative actions. In such contexts, cross-species grooming might be less about deliberate cooperation and more an opportunistic extension of customary preening behaviors to the nearest conspecific or heterospecific partner.
From a research standpoint, these episodes underline the value of community-collected imagery in revealing rare or ephemeral behaviors. Photographs and short videos supply verifiable timestamps and visual confirmation, which can be triaged for follow-up field studies. If interspecific allopreening proves more common than assumed, it would prompt reevaluation of social interaction models in multi-species assemblages and potentially affect interpretations of parasite dynamics and disease transmission.
Comparison & Data
| Date | Location | Species | Approx. Duration |
|---|---|---|---|
| Feb. 4, 2023 | Phil Hardberger Park, San Antonio | Crested caracara & Black vulture | Photographed (duration not precisely recorded) |
| 2022 (approx.) | Rooftop ~1 mile from park | Crested caracara & Black vultures | About 20 minutes (observer estimate) |
The table summarizes the two publicly reported events tied to San Antonio observers. Both entries are based on photographic or eyewitness records rather than quantitative behavioral studies, so duration and frequency estimates are approximate. These snapshots highlight how urban-adjacent settings concentrate species and observers, making such interactions more likely to be noticed and shared.
Reactions & Quotes
Observers and local naturalists reacted with surprise and curiosity; their firsthand comments helped spur wider attention among birding networks. Ornithologists contacted by local media noted that, while rare in the literature, interspecific preening could be underreported and merits systematic study.
“It was just very weird to see that,”
Lora Reynolds, Bexar Audubon volunteer
Reynolds emphasized her long experience birding in the region and said the sighting stood out precisely because it departed from the usual pattern of intraspecific grooming. Her images were instrumental in circulating the observation to a broader audience.
“It looked like a rooftop party,”
Lori Boies, local biologist and photographer
Boies described multiple birds interacting amicably on a rooftop in the year before the park sighting. Her account reinforced that the Phil Hardberger Park episode was not an isolated curiosity but part of a small cluster of local reports.
Unconfirmed
- Whether the Phil Hardberger Park interaction served primarily to remove parasites rather than to signal social tolerance is not confirmed; no parasite sampling was conducted.
- It is unclear how widespread interspecific allopreening is across other urban or wild landscapes—existing reports may undercount true occurrence.
- No formal behavioral study has yet linked these San Antonio observations to long-term changes in interspecies tolerance or partnership.
Bottom Line
Photographic and eyewitness records from San Antonio in 2022–2023 document crested caracaras and black vultures engaging in interspecific preening, a behavior rarely recorded in the academic literature. These cases, collected and shared by community scientists and park staff, suggest that cross-species grooming might be more common—at least in human-influenced habitats—than previously appreciated.
To move from anecdote to understanding, researchers need systematic field observations and targeted studies that measure frequency, context and potential benefits such as parasite removal. In the meantime, community photographs and careful reporting provide valuable, verifiable leads that can shape future ornithological research and monitoring.