WildAgain Wildlife Rehabilitation, Inc.

home > rehab record study

Download the complete report here











wildlife emergency


contact us



A Study of Annual Reports of Wildlife Rehabilitators for the Five Year Period 1998-2002

The complete 27 page report, including all of the photos, tables, graphs and complied data, is available as a pdf file and can be downloaded by clicking here. The information that is presented below is excerpted from the full report, and provides an overview of the purpose and methodology of the study, as well as a summary of some of the more significant findings.



Wildlife rehabilitators provide temporary care for injured, orphaned, or otherwise distressed wild animals with the goal of releasing healthy animals that can survive independently in their native environment. While wildlife is rehabilitated in many areas and rehabilitators maintain and review their own records, there have been relatively few quantitative studies conducted about wider demographics and trends related to wildlife rehabilitation.

Believing such quantitative data would be useful, we conducted a study to quantify the demographics and caseload activity of wildlife rehabilitators in Colorado. Annual wildlife rehabilitation records submitted to the Colorado Division of Wildlife by each rehabilitator, which list each animal that was admitted into rehabilitative care, were used for this analysis. The Colorado Division of Wildlife provided this information as a result of a Colorado Open Records Act request.

This report compiles, tabulates and analyzes the data that was reviewed for the time period 1998 through 2002. The findings are presented without attempting to draw subjective conclusions concerning the reason behind certain data or trends that became evident during the analysis.

While this study provides some useful information, it also serves to identify many questions needing answers.  We believe that only through conducting this type of research and analysis can we as a wildlife rehabilitation community begin to understand the many dynamics at play in our efforts to help wild animals.

Purpose of the Study

This study was conducted in order to quantify and analyze demographics and metrics about the wildlife rehabilitation community in Colorado. Most previous analyses that described the nature and activity level of state rehabilitators were based on rough estimates. This study is intended to quantify many aspects of the community, such as caseload statistics and release metrics, as well as provide a more in-depth and complete view of the demographics of licensed rehabilitators.

Study Methodology

The scope of the study involved reviewing the Annual Species reports submitted to the Colorado Division of Wildlife (CDOW) for the five-year time period 1998 through 2002. Submission of the Annual Species Report is a regulatory requirement of all license holders, and is a prerequisite to the annual renewal of the license. The report, due no later than January 31 of each year, indicates all activity for the past year for the rehabilitation license holder, and contains information about each animal admitted for rehabilitation. The content of the report is specified in regulation.

We submitted a Colorado Open Records Act (CORA) request in early summer of 2003, in order to schedule a review of the Annual Species reports that are maintained by the CDOW’s Special Licensing office. The CORA request was approved by the Attorney General’s office. We reviewed the reports at CDOW’s Colorado Spring’s regional office in two sessions in the summer of 2003. 

Data Gathering

The data gathering was designed as a three-part process. The first step was to review each report for certain data and counts of animals by type or group of species, and by the animal’s final disposition.

The second step was to pick a random sample of animals from the reports to better understand the number and types of species of animals that are admitted for rehabilitation; their length of time in captivity; and survivability and release rates. A laptop computer-based random number generator program was used to select five entries from each Annual Species Report to record on a separately designed form for such purpose.

The third step of the data gathering was to look at information for each rehabilitator, including name, license number, city or location where the rehabilitator was licensed, and which of the five years the rehabilitator held the license.

Data Analysis

The data collected was subsequently input into a series of electronic spreadsheets for analysis. The analysis was performed in the offices of WildAgain Wildlife Rehabilitation, Inc. in Evergreen, Colorado during the spring of 2004.

As the data was reviewed and analyzed, five primary groupings or categories of information emerged. These categories are as follow:

1.) Wildlife rehabilitator demographics (e.g., number, location, experience level, attrition)

2.) Animal caseload (e.g., number of animals, species, seasonality and timing, transfers)

3.) Caseload distribution (e.g., variation of caseload numbers between rehabilitators)

4.) Survivability during rehabilitation (e.g., critical first days, overall percentage of survivors by species)

5.) Release of animals (e.g., length of stay in captivity, release rates)

The results and findings of the study are presented using these five categories.

A Quick Summary of the Results

The review of 405 Annual Species reports submitted by 177 licensed wildlife rehabilitators to the Colorado Division of Wildlife during the time period 1998 through 2002 involving 53,000 animals indicated the following statistics and trends:

Wildlife rehabilitator demographics in Colorado

On average, there were 106 licensed rehabilitators per year.

The net number of rehabilitators increased on average 6% per year, with a total of 117 in 2002.

From the prior year, non-renewals averaged 17%. New recruitment averaged 23%.

Attrition of new license holders exceeded 20% in the first year and 50% over three years.

The median experience of 117 rehabilitators in 2002 was 4 years.

License holders were 75% female, 25% male.

Home-based facilities accounted for 95% of all license holders.

The large majority of Colorado rehabilitators were located on the more urbanized Front Range, with 75% of the rehabilitators located 50 miles either side of Interstate 25 from Pueblo to Ft. Collins, and with 20% on the Western Slope.

There were about an equal percentage of rehabilitators who rehabilitated avian species (61%) and mammal species (62%). Thirty-seven percent rehabilitated both avian and mammal species.

Animal caseload

The reports reviewed indicated approximately 53,000 animals were rehabilitated statewide during the 5 years (averaging 10,600 per year).

Annual caseload statewide increased 8% per year overall (up a total of 36% from 1998 to 2002).

A total of 69% of the animals rehabilitated were avian (mostly passerines). The rehabilitated mammals totaled 28% and were mostly small (e.g., squirrels, rabbits) to mid-sized (e.g., raccoons, fox). Two percent of the animals rehabilitated were bats and one percent were herptiles.

Most animals (80%) arrived for rehabilitation between April 1 through September 30, with 54% of the total arriving in the 90-day period May 1 through July 31.

Rehabilitators provided an estimated 1.8 million days of patient care to wild animals (calculated during the five year period by the average length of stay times the number of animals).

Animal caseload distribution

Half of the rehabilitators each see 20 animals or less per year (only 2% of total animals). Two-thirds of the rehabilitators see 50 animals or less per year (only 7% of total animals).

Five percent of the rehabilitators each see over 500 animals per year (66% of total animals in the state).

On average, 6% of the total number of animals each year were transferred by and between rehabilitators for workload distribution or training purposes, or for special expertise or caging requirements. 

Survivability of animals

A randomly selected sample of 949 animals (2% of total) from the Annual Species reports were reviewed and indicated the following:

Birds died or were euthanized at twice the rate of mammals in the first 4 days of captivity.

One-third (33%) of all birds admitted to rehabilitation died or were euthanized in the first 4 days of captivity. Sixty percent of all birds admitted eventually survived.

One-sixth (17%) of all mammals admitted to rehabilitation died or were euthanized in the first 4 days of captivity. Seventy-three percent of all mammals admitted survived.

Of all animals (all species) that died or were euthanized (33% of the sample), the death or euthanasia occurred early in captivity (60% within the first 2 days; 80% within 5 days).

Release of animals

Just over three-fourths of all animals were in captivity less than 60 days. About 95% of all animals were in captivity 120 days or less. The average stay was 35 days.

Less than 1% of all animals were in captivity more than the 180-day limit mandated by Colorado rehabilitation regulations. Of these, most were pending at year-end for continuing medical treatment, molt, hibernation, or to be released at the appropriate time of year for the species (e.g., migration).

In the sample analyzed, over 94% of animals listed as ‘pending’ at year-end were eventually released.

Because a small group (only 5%) of all rehabilitators see two-thirds of all animals in the state, overall release rates were calculated two ways – first, based on average of all animals, and second, based on the average release rate experienced by all rehabilitators, regardless of their caseload size.

The average release rate was 67% when calculated based on the average release rate experienced by all rehabilitators, regardless of their annual caseload numbers.

The average release rate was 52% when calculated based on all animals statewide. (This 30% difference in average release rate was heavily influenced by the lower percentage of animals released by rehabilitators with larger caseloads).

On average, release rates trended lower for rehabilitators with higher annual caseloads (those with 100+ animals).


Closing Comments

The results of this project shows the type of data and quality of insights that can be gained from using information submitted by rehabilitators via their annual reports to their governing state wildlife agency. Significant information can be gleaned from examining wildlife rehabilitator demographics and reported caseload results over a five-year period for a single state. The same study could easily be replicated in other states since most state wildlife agencies require submission of an annual report containing similar data as a condition of permit renewal. Additional studies similar to the one presented in this report should be conducted before suggesting meaningful trends or conclusions on a national level.

While this study reveals certain statistics and trends, it prompts many more questions. We consider these questions as opportunities for further research within the rehabilitation community, both at the state and national levels.  For example, the study indicates some potentially interesting numbers concerning release rates.  Since there are, however, many factors that can influence rates of release (e.g., regulations, policies, classifications/coding, species, age of animals), it can be challenging to compare release rates between rehabilitation facilities as well as between states.  It will be necessary to conduct further research into identification and assessment of release factors before their meanings can be understood.  Research and study are needed to identify and understand the reasons for, and ways to, address the high attrition rate of rehabilitators.  It also would be helpful to look at the reasons for a significantly higher release rate of mammals, as well as trends in rehabilitation caseloads.  And the list goes on.

In the meanwhile, we think that this type of report can be useful for many purposes, especially if the results are applied to a specific facility or geographic area.  For instance, information could help with planning for rehabilitation caseload, facility development, recruiting, and purchasing of supplies.  Because they indicate the overall and beneficial impact of wildlife rehabilitation activities, these data and statistics are potentially supportive of fundraising.  They also may be considered as input when reviewing the need for changes in the state regulations that govern wildlife rehabilitation, as well as for identifying training needs and when/where to offer such training.

We encourage you to download the complete 27 page study report as it discusses the results in much more depth, including providing various charts, tables and graphs. If you have interest in performing the same study for your state, region or facility, please contact us and we can discuss more specifics as to data collection planning and methodology.



Casey, Allan and S. Casey. 1994. Survey of state regulations governing wildlife rehabilitation. Journal of Wildlife Rehabilitation, Winter: 6-10.

Casey, Allan and S. Casey. 1995. State regulations governing wildlife rehabilitation: A summary of best practices. Journal of Wildlife Rehabilitation, Spring: 3-11.

Casey, Allan and S. Casey. 2000. Survey of state regulations governing wildlife rehabilitation during 1999. Wildlife Rehabilitation: National Wildlife Rehabilitators Association – selected papers from the annual symposium: 173-192.

Casey, Allan and S. Casey. 2005. Survey of state regulations governing wildlife rehabilitation: 1994-2004. National Wildlife Rehabilitators Association, presentation at the annual symposium.


Copyright 2005. © WildAgain Wildlife Rehabilitation, Inc. All Rights Reserved unless otherwise stated.