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Managed Cats as a Wildlife Conservation Strategy

HAA Coexistence Framework - Snapshot Brief
Hawaiʻi Animal Advocacy

About the Author & HAA Founder

Greg Puʻuwai Aloha Baker is an emerging Hawaiʻi-based humane, science-based cat population management expert whose work uniquely integrates field colony management, high-volume sterilization, formal population-management training, scientific research, conservation analysis, and public-policy development. 

5 years managing 8 community-cat colonies, at times caring for 120+ cats seven nights a week • 120+ cats personally trapped/TNR’d • 4,500+ sterilizations supported through PetFix • 30+ home cat sanctuary • college certificate in cat population management • authored 24+ science-based cat briefs • Hawaiʻi legislative and DLNR testimony • creator of the Coexistence Framework, CEAS, and Managed Cats management doctrine. 

Baker’s work bridges the gap between hands-on cat management, conservation science, and government policy—bringing each into one integrated population-management approach.

The Core Findings

The evidence reviewed in this brief supports two important conservation findings:

• First, reliable, nutritionally adequate feeding can reduce bird predation by reducing cats’ hunting activity and their reliance on wild prey.

• Second, sterilization can substantially reduce roaming - particularly among adult males - which reduces the area over which cats can encounter and prey on birds.

Together, these findings show that managing community cats can directly reduce important pathways of bird predation while simultaneously controlling reproduction and reducing the cat population over time. Key findings like this are significant and provide important foundational support for the Coexistence Framework.

These conclusions are supported by several different types of research. Controlled feeding experiments have measured reductions in prey capture after nutritional intervention. Fecal analysis has found substantially greater wild-vertebrate predation among poorly fed cats than adequately fed cats. Stable-isotope studies show consistently provisioned cats shifting away from wild prey and toward commercial food. Large contemporary studies of provisioned cats find that most are not reported hunting at all. Separately, radio-telemetry and GPS studies show that sterilization can dramatically reduce roaming, including reductions in male home range and daily travel.

The conservation implication is significant because cats that are fed, sterilized, monitored, and managed are not ecologically equivalent to cats that reproduce freely, roam widely, and depend more heavily on natural prey. Management changes both how much cats need to hunt and how much opportunity they have to encounter birds.

This does not mean that feeding or sterilization eliminates all bird predation, or that managed cats can never present a significant risk in sensitive locations. It means that the available evidence supports management as a practical way to reduce bird predation while reducing the cat population itself. That makes managed community-cat programs more than an animal-welfare or population-control strategy; they can also function as a bird-conservation strategy.

The Coexistence Framework builds on this evidence through a two-step approach. First, implement the managed-cat protocol “Feed • Fix • Monitor • Manage • Prevent” to reduce hunting, reliance on wild prey, roaming, reproduction, and opportunities for cat-bird interactions. Second, apply the Conservation Evidence & Accountability Standard (CEAS) to determine whether the remaining cat predation is still large enough to function as a population-limiting factor and whether bird populations are responding positively or not.

This creates a simple conservation method: manage the cats first, then measure whether bird populations benefit.

Section 1.  Reliable Feeding Reduces Hunting and Reliance on Wild Prey

The evidence supports a consistent pattern: cats receiving reliable, nutritionally adequate food hunt less and rely less on wild prey than cats that are poorly fed or more dependent on natural prey.

This relationship appears across several independent research methods, including controlled feeding experiments, fecal prey analysis, stable-isotope analysis, and large observational studies of provisioned cats. Feeding does not eliminate hunting in every cat, but it can materially reduce the need to obtain calories from wildlife and therefore represents an important bird-predation-reduction component of managed-cat programs.

• Most cats in this large predominantly provisioned population were not reported hunting. In this study of more than 2,400 predominantly commercially fed cats, about 77% were reported not to hunt.

• Adequately fed cats were far less likely to prey on wildlife than poorly fed cats. In a study that included fecal prey analysis, poorly fed cats had 4.7 times greater odds of preying on wild vertebrates than adequately fed cats.

• Changing what cats were fed reduced measured predation. In a controlled experiment, cats given a nutritionally complete high-meat-protein diet brought home 36% fewer prey animals, providing direct experimental evidence that better nutritional management can reduce hunting.

• Dietary evidence confirms that regular provisioning can move cats away from wildlife prey. Stable-isotope analysis showed consistently provisioned cats shifting from wild prey toward commercial food, providing a biological measure of reduced dependence on hunting for food.

These findings do not establish that every provisioned cat stops hunting. They do show the same directional relationship across different methods: adequate provisioning is associated with less hunting and lower reliance on wildlife prey.

Study: Influence of Care of Domestic Carnivores on Their Predation on Vertebrates

Silva-Rodríguez & Sieving (2011), Conservation Biology
Study link:  https://pubmed.ncbi.nlm.nih.gov/21658128/  

What the study examined: Researchers evaluated whether the level of human care and food provision given to domestic cats influenced their predation on wild vertebrates. Importantly, the study incorporated analysis of prey remains in feces rather than relying only on caretaker observations.

Key finding: Poorly fed cats were much more likely to prey on wildlife. Cats receiving inadequate food had 4.7 times greater odds of preying on wild vertebrates than adequately fed cats.

Why it matters: In practical terms, the study found a strong relationship between inadequate feeding and greater reliance on wildlife as prey. Because the study included fecal prey evidence, it also helps address the concern that caretakers may fail to observe prey that cats kill or consume away from home.

Study: Provision of High Meat Content Food and Object Play Reduce Predation of Wild Animals by Domestic Cats

Cecchetti et al. (2021), Current Biology
Study link: https://www.sciencedirect.com/science/article/pii/S0960982220318960

What the study examined: This controlled intervention tested whether changing cats’ diet and enrichment could reduce predation by free-ranging domestic cats.

Key finding: Improving cats’ nutrition measurably reduced their hunting. Providing a nutritionally complete high-meat-protein food resulted in 36% fewer prey animals being captured and brought home.

Why it matters: Because researchers changed the cats’ diet and then measured the subsequent change in prey returned home, this provides direct experimental evidence that nutritional management can reduce predation behavior. The study did not measure every kill that may have occurred away from home, so the result is most accurately described as a reduction in prey captured and brought home.

Study: Evaluating the Effects of Managed Free-Roaming Cat Populations on Prey Through Stable Isotope Analysis

Martinoia et al. (2025), Animals
Study link:  https://www.mdpi.com/2076-2615/15/21/3204

What the study examined: Researchers used stable-isotope analysis to evaluate dietary change among free-roaming cats exposed to sustained food provision and sterilization.

Key finding: Consistent provisioning was associated with cats shifting away from wild prey and toward commercial food. Dietary signatures narrowed and moved toward the profile associated with commercially fed cats. Cats already receiving regular food before sterilization showed similar dietary patterns, supporting provisioning as an important contributor to the dietary change.

Why it matters: Stable-isotope analysis provides evidence of what cats assimilated into their diets over time rather than depending on whether prey was observed or brought back to a caretaker. This strengthens the evidence that regular feeding can reduce actual dependence on wildlife prey.

Study: Birds are Still Singing in Our Suburbs: Contemporary Hunting Data for Pet Cats in Urban Australia

Rand et al. (2026), preprint
Study link: https://www.preprints.org/manuscript/202609.1612

What the study examined: Researchers collected hunting and feeding information for more than 2,400 owned and semi-owned cats participating in a community sterilization program. The cats were overwhelmingly provisioned, with commercial food forming the primary diet for most of the population.

Key finding: Most provisioned cats were not reported hunting. Among more than 2,400 predominantly commercially fed cats, about 77% were reported not to hunt, providing large-scale evidence that hunting was uncommon in this provisioned cat population.

Why it matters: Although the study is presently a preprint and hunting was largely caretaker-reported, its large sample provides useful contemporary evidence that hunting is not universal among provisioned outdoor-access cats. It also reinforces the importance of distinguishing nutritionally supported cats from cats that are more dependent on natural prey.

Section 2.  Cats More Dependent on Natural Prey Show Higher Predation

Research on feral cats provides important context for the feeding studies. Cats living where they depend more heavily on natural prey tend to show substantially greater wildlife consumption than cats living in human-modified environments where alternative food sources are more available. These studies are not controlled feeding experiments, so they cannot establish that provisioning alone caused the difference. They nevertheless reinforce the broader pattern that the degree of dependence on natural prey matters when evaluating bird predation.

Key findings from the research

• Australian researchers estimated approximately 129 birds per feral cat per year in largely natural landscapes.

• The estimate for feral cats in highly modified landscapes was approximately 61.5 birds per cat per year.

• That represents an estimated bird-predation rate approximately 52% lower in the highly modified environment.

• The result is consistent with, but does not by itself prove, the hypothesis that greater availability of human-derived food reduces reliance on wild prey.

Study: How Many Birds Are Killed by Cats in Australia?

Woinarski et al. (2017), Biological Conservation
Study link:  https://www.sciencedirect.com/science/article/abs/pii/S0006320717302719

What the study examined: Researchers synthesized dietary and predation information from feral and pet cats across Australia to estimate national bird mortality attributable to cats.

Key finding: Feral cats living in natural landscapes were estimated to kill substantially more birds than feral cats in heavily human-modified landscapes. Estimated predation was approximately 129 birds per cat per year in natural landscapes compared with about 61.5 birds per cat per year in highly modified landscapes.

Why it matters: The study should not be interpreted as a controlled feeding experiment. Its importance here is contextual: cats living in environments where they were more dependent on natural prey showed substantially greater estimated bird predation than cats living in heavily human-modified settings where human-derived food is more available.

Viewed alongside the controlled feeding, fecal, isotope, and provisioned-cat studies, the result contributes to a broader evidence pattern: bird-predation risk cannot be evaluated accurately without considering whether cats are nutritionally supported or dependent upon natural prey.

Section 3.  Sterilization Can Substantially Reduce Roaming and Access to Wildlife

Sterilization provides a second bird-protection pathway beyond preventing births. Several tracking studies indicate that sterilization can substantially reduce ranging behavior, particularly among adult males whose movements are influenced by reproduction. When cats travel over smaller areas and spend less time ranging through natural habitat, they have fewer opportunities to encounter birds and other wildlife. The magnitude varies by sex, age, habitat, food availability, and individual behavior, so sterilization should not be expected to produce identical results in every cat.

Key findings from the research

• Sterilization substantially reduced how far male cats ranged. In a before-and-after telemetry study, male home range declined about 79%, activity declined about 29%, and overlap with natural areas decreased—reducing opportunities for cats to encounter birds.

• A newer GPS study independently found the same pattern. Adult male daily travel declined about 44–53% after neutering, reinforcing the evidence that sterilization can substantially reduce roaming and opportunities for bird encounters.

• Male home range declined approximately 79.3% after castration in one before-and-after radio-telemetry study.

• Activity in the same study declined approximately 28.7%, and overlap with natural areas decreased.

• A newer GPS study found adult male daily travel declining approximately 44–53% after neutering.

• Other field research has found substantially larger ranges among intact cats than among sterilized cats living around regular feeding areas.

Study: The Effect of Castration on Home Range Size and Activity Patterns of Domestic Cats Living in a Natural Area in a Protected Area on a Brazilian Island

Ferreira et al. (2020), Applied Animal Behaviour Science
Study link:  https://www.sciencedirect.com/science/article/pii/S0168159120301374

What the study examined: Researchers used radio telemetry to track male cats before and after castration, allowing changes in movement and habitat overlap to be measured within the same animals.

Key finding: Castration dramatically reduced how far the cats ranged. Average home-range size declined by approximately 79.3%, activity declined by approximately 28.7%, and use of natural areas decreased.

Why it matters: A smaller range means fewer opportunities for cats to enter natural habitat and encounter birds. The findings show that sterilization can alter more than reproduction; it can also change the spatial relationship between cats and wildlife.

Study: Longitudinal GPS Monitoring of Male Cats Before and After Neutering

2026 GPS tracking study, Applied Animal Behaviour Science
Study link:  https://www.sciencedirect.com/science/article/pii/S0168159126002327

What the study examined: Researchers followed individual male cats using GPS before and after neutering to measure changes in daily travel and home-range size.

Key finding: Adult males traveled substantially less after neutering. Two adult males reduced daily travel by approximately 53% and 44%, with substantial contractions in home range. A juvenile did not show the same pattern.

Why it matters: The study independently supports the proposition that neutering can reduce adult male roaming while also showing that age and individual differences matter. Reduced roaming decreases the area over which cats have opportunities to interact with birds.

Study: Home Range and Habitat Use of Free-Roaming Cats on Farms

Horn et al. (2015)
Study link:  https://pmc.ncbi.nlm.nih.gov/articles/PMC4403806/

What the study examined: Researchers tracked farm cats to evaluate home-range size, habitat use, sex, reproductive status, and proximity to human food resources.

Key finding: Intact cats ranged farther, while sterilized cats remained more concentrated around the area where food was regularly available. Intact cats had substantially larger ranges than sterilized cats, and the core ranges of sterilized cats clustered near the common feeding area.

Why it matters: The findings are consistent with two complementary mechanisms in managed populations: reliable food can spatially anchor cats, while sterilization can reduce reproductive roaming. Together, these changes can reduce the geographical area in which cats encounter birds.

Section 4.  Management Works Because Several Predation-Reduction Effects Occur Together

The Coexistence Framework does not treat feeding, sterilization, or monitoring as isolated interventions. The bird-conservation benefit comes from combining them. Feeding reduces nutritional dependence on prey; sterilization prevents births and can reduce roaming; monitoring identifies new arrivals, persistent hunters, and sensitive locations; continued management maintains accountability and allows the program to adapt as conditions change.

The Managed-Cat Protocol

A sterilized cat without adequate food may still rely substantially on prey. A fed cat that continues reproducing adds new animals to the population. Feeding and sterilization without monitoring can allow abandonment, immigration, or persistent high-risk behavior to go unnoticed. The Framework therefore depends upon the interventions working together rather than treating any single activity as the complete solution.

The expected conservation pathway is straightforward:   fewer births + less reliance on prey + less roaming + continued monitoring  =  fewer opportunities for cats to prey on birds.

Section 5.  Independent Evidence Methods Point in the Same Direction

No individual study proves that every managed-cat population will produce the same bird-conservation outcome. The scientific strength comes from independent research methods reaching compatible findings. Controlled interventions show reduced prey capture; fecal analysis links inadequate feeding with substantially greater wild-prey use; stable isotopes show dietary movement away from wildlife; large contemporary observations find most provisioned cats not hunting; and telemetry and GPS studies show that sterilization can markedly reduce ranging.

Because these studies differ in location, population, methodology, and research group, the convergence is more informative than relying upon any single statistic. Together, the evidence supports managed-cat programs as a scientifically plausible and measurable means of reducing several pathways through which cats prey upon birds.

6. The Coexistence Framework Uses a Two-Step Conservation Method

Reducing cat-related bird predation is only the first part of the Framework. The second is determining whether the remaining level of predation actually matters to the bird population. This distinction is essential because evidence that a cat can kill an individual bird is not the same as evidence that cats are causing a bird population to decline or preventing its recovery.

Step 1 — Implement the Managed-Cat Protocol

The first step is to Feed • Fix • Monitor • Manage • Prevent New Cats. The objective is to reduce reproduction, hunting pressure, reliance on natural prey, roaming, and opportunities for birds and cats to encounter one another while making the cat population stable, observable, and accountable.

Step 2 — Apply CEAS and Test the Bird-Population Outcome

Once cat-related impacts have been reduced through management, the Conservation Evidence & Accountability Standard asks whether the remaining effect rises to the level that matters for conservation. CEAS examines whether cats remain a primary or secondary population-limiting factor, whether bird populations are improving or stabilizing, what other factors are affecting recovery, and whether additional intervention is supported by the evidence.

This produces a simple adaptive-management cycle:  Manage → Measure → Test → Adapt

The Framework does not assume in advance that management will always be sufficient. It establishes a lower-risk managed condition and then measures whether bird-population outcomes demonstrate that additional intervention is necessary.

Section 7. Why This Matters for Hawaiʻi's Endangered Birds

Hawaiʻi provides an especially important setting for distinguishing individual predation from population-level conservation effects. Cats are documented predators of some native birds and may present significant risk at particular nesting colonies or sensitive locations. That does not mean cat predation is automatically the factor limiting recovery of every endangered bird population.

A CEAS review of 20 endangered Hawaiian birds found that cats were not identified as the primary or secondary limiting factor for those species, even though cats may appear as documented predators or threats for some species and locations. The distinction is critical because conservation action should ultimately address the factors that are actually limiting population persistence or recovery.

The Framework therefore asks two questions in sequence;

• First, can known cat-related predation be reduced through management? The research summarized in this brief indicates that several pathways can.
• Second, after those impacts have been reduced, do cats still exert enough population-level pressure to limit bird recovery? CEAS is designed to answer that second question.

Where evidence demonstrates that cat predation remains significant in sensitive habitat, additional measures such as exclusion, relocation, targeted deterrence, enhanced monitoring, or other protections may be appropriate. Where cat predation is not population-limiting, conservation resources can remain concentrated on the factors actually preventing recovery.

Section 8.  The Policy Comparison Should Be Managed Cats Versus Unmanaged Cats

Much of the public discussion about cats and birds implicitly compares the presence of cats with an idealized condition in which cats are absent. In many communities, however, cats already exist and cannot be made to disappear immediately. The practical conservation decision is therefore often between different ways of managing the cats that are present.

This distinction also matters when considering feeding restrictions. If adequate food provision reduces hunting and reliance on wildlife prey, then food withdrawal should not automatically be assumed to reduce bird predation. Existing cats do not disappear when food is removed, and the resulting behavioral response should be measured rather than presumed.

Likewise, dismantling a managed-cat program can mean losing not only feeding but sterilization, monitoring, population accountability, and the ability to respond adaptively to bird-conservation concerns.

Section 9.  What the Evidence Supports — and What It Does Not

The available research does not demonstrate that every fed cat stops hunting, that sterilization eliminates all roaming, or that managed cats can never affect sensitive bird populations. It also does not establish that every managed population automatically improves bird-population trends.

What the evidence does support is more directly useful for conservation: management changes the pathways through which cats prey upon birds. Reliable feeding can reduce prey capture and dependence on wildlife; sterilization prevents births and can substantially reduce adult male roaming; monitoring allows persistent hunters and sensitive locations to be identified; and coordinated management provides a stable population that can be measured and adapted.

This is why the Coexistence Framework treats management as the starting intervention rather than the final assumption. Management reduces the potential for cat predation first. CEAS then determines whether the remaining impact is large enough to matter at the population level.

Conclusion

This review brings together several lines of evidence that are often discussed separately.

When they are examined together, a clear pattern emerges: managing community cats can reduce bird predation and reliance on wild prey while simultaneously controlling the cat population itself.

The most important findings include:

• Most provisioned cats in a large Australian study were not reported hunting.  Among more than 2,400 cats, 77% were reported not to hunt at all. Hunting was reported in 20.5% of cats not fed raw meat versus 30.6% of cats fed raw meat, suggesting that feeding type and nutritional adequacy may influence hunting behavior.

• Sterilization substantially reduced how far male cats ranged. In a before-and-after telemetry study, male home range declined about 79%, activity declined about 29%, and overlap with natural areas decreased—reducing opportunities for cats to encounter birds.

• A newer GPS study independently found the same pattern. Adult male daily travel declined about 44–53% after neutering, reinforcing the evidence that sterilization can substantially reduce roaming and opportunities for bird encounters.

• Adequately fed cats were far less likely to prey on wildlife than poorly fed cats. In a study that included fecal prey analysis, poorly fed cats had 4.7 times greater odds of preying on wild vertebrates than adequately fed cats.

• Changing what cats were fed reduced measured predation. In a controlled experiment, cats given a nutritionally complete high-meat-protein diet brought home 36% fewer prey animals, providing direct experimental evidence that better nutritional management can reduce hunting.

• Dietary evidence confirms that regular provisioning can move cats away from wildlife prey. Stable-isotope analysis showed consistently provisioned cats shifting from wild prey toward commercial food, providing a biological measure of reduced dependence on hunting for food.

Each study has its own limitations, and no single result proves the entire case. But together they are difficult to ignore. Different researchers, countries, study populations, and measurement methods are all pointing toward the same general conclusion: reliable feeding reduces dependence on wild prey, sterilization can reduce roaming, and managed cats as a population have fewer opportunities and less need to prey on birds.

That matters because a fed, sterilized, monitored community-cat population is not ecologically equivalent to an unmanaged population that reproduces freely, ranges widely, and relies more heavily on natural prey. Treating both populations as though they present the same level of bird-predation risk overlooks what the research is showing about the effects of management.

The findings therefore provide a strong scientific rationale for the Coexistence Framework. Community-cat management is not simply a humane way to control cat populations. It can also function as a bird-conservation strategy by reducing several of the conditions that contribute to predation: inadequate nutrition and reliance on prey, reproductive roaming, uncontrolled population growth, and unmonitored movement into sensitive areas.

 The next step is equally important. The Framework does not assume that reducing cat predation automatically solves every conservation problem. After cats are managed, CEAS asks whether the remaining level of predation is still large enough to limit a bird population and whether that population actually improves, stabilizes, or continues to decline.

The conservation method is therefore straightforward:

Step 1 — Manage the cats.
Feed • Fix • Monitor • Manage • Prevent New Cats.

Step 2 — Test the bird-population outcome.
Determine whether cat predation remains population-limiting and whether bird populations respond.

Where cat predation remains significant in a sensitive location, management can be strengthened through exclusion, relocation, deterrence, enhanced monitoring, or other targeted measures. Where cat predation is reduced below a population-limiting level, conservation attention can remain focused on the factors actually preventing bird recovery.

The combined finding is powerful: community-cat management can address both sides of the equation at the same time—fewer cats over time and less predation pressure from the cats that remain. That gives conservation a practical pathway that does more than debate whether cats can harm birds. It actively reduces the conditions that contribute to predation and then measures whether the reduction is enough.

This is an important statement to acknowledge: “We manage community cats not instead of protecting birds, but as one way of protecting birds!”

Managed Cats provides Population Management and Bird Protection.

About Hawaiʻi Animal Advocacy 

 Hawaiʻi Animal Advocacy is a Hawaiʻi-based organization focused on science-based, humane policy for animal population management. HAA works at the intersection of animal welfare, conservation, public health, and community stewardship.  The organization promotes evidence-based strategies that address the root causes of free-roaming animal populations while supporting protection of native wildlife, ecosystem health, and community well-being. 

 HAA recognizes that conservation challenges in Hawaiʻi are complex and multifactorial, involving habitat loss, invasive species, disease, watershed degradation, climate pressures, and human activity. Effective management therefore requires integrated, measurable, and publicly accountable approaches rather than single-factor responses.

The organization supports humane population stabilization through targeted sterilization programs, responsible colony management, adoption pathways, public education, and collaborative community engagement. HAA also supports improved scientific rigor, transparent policymaking, and management strategies grounded in verifiable evidence and real-world outcomes. 

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