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Department of Fish & Wildlife
Biogeographic Data Branch
1700 9th Street, 4th Floor
Sacramento, CA 95811
1416 9th Street, Suite 1266
Sacramento, CA 95814
(916) 322-2493 • Email BDB
Spotted Owl Observations Database FAQs
Frequently Asked Questions (FAQs)
- What recent changes were made to the database?
In 2012, the Department’s Biogeographic Data Branch (BDB) made numerous changes to the Spotted Owl Observations Database. Most notably, BDB released an updated spatially-enabled version of the database for use with the Biogeographic Information and Observation System (BIOS layer ds704). In addition to displaying the locations of owl activity centers, the updated Spotted Owl Observations layer now includes the locations of the observations associated with owl activity centers, both positive and negative (attribute "TYPEOBS" where: AC = activity center, POS = positive observation, and NEG = no owls detected). Additionally, BDB created the Spotted Owl Observations Spider Diagram layer depicting the relationship between activity centers and observations (BIOS layer ds705). In late November, BDB changed the way that "not valid" and "permanently abandoned" activity centers are represented in the BIOS layer and altered the database rules to allow negative observations to show up on the map without being explicitly associated with an activity center. Finally, the reports generated from the updated Spotted Owl Observations layer have a new format and contain slightly different information than the reports from the older (and now outdated) Spotted Owl Territories layer (ds97). In addition to Public Land Survey System (MTRS) information, the new report format contains latitude and longitude coordinates. The reports also display the coordinate source for each observation to help users assess the precision of owl locations.
- What does the MASTEROWL number represent?
Generally, each unique MASTEROWL number is associated with a cluster of related observations in the same geographic area. Usually (but see below), one and only one observation per MASTEROWL number is designated as an "Activity Center." The MASTEROWL number does not explicitly refer to an individual owl or pair of owls, and is not necessarily synonymous with an owl’s "territory." The group of observations that share a MASTEROWL number are best thought of as a survey history for a known Spotted Owl site, i.e., a patch of habitat that is currently occupied (or has been occupied in the past) by one or more Spotted Owls. The spider diagram aids in visualizing the geographic extent of the site and shifts in habitat use over time.
- What constitutes an "Activity Center?"
"Activity Center: Spotted owls have been characterized as central-place foragers, where individuals forage over a wide area and subsequently return to a nest or roost location that is often centrally-located within the home range" (Rosenberg and McKelvey 1999). Activity centers are a location or point within the core use area that represent this central location. Nest sites are typically used to identify activity centers, or in cases where nests have not been identified, breeding season roost sites or areas of concentrated nighttime detections may be used to identify activity centers" (U.S. Fish and Wildlife Service 2011).
- MASTEROWL group "NEG" has no Activity Center and has observations all over the state. Is this a mistake?
No. MASTEROWL "NEG" consists exclusively of negative observations (i.e., surveys where no owls were detected) that were not conducted in close proximity to a known Spotted Owl site. We feel that it is misleading to assign a negative observation to a MASTEROWL group if the associated site was not actually called or searched.
- There are some MASTEROWL groups that have an "NVAC" or "ABAN" observation instead of an Activity Center. What do these codes mean?
The U.S. Fish and Wildlife Service is often asked to provide technical assistance (TA) during review of timber harvest plans or other operations that may affect Northern Spotted Owls. Occasionally, the Service determines that an existing Activity Center is "not valid" (e.g., resident single or pair status was never established). In these cases, we change the code for the Activity Center from AC to NVAC ("Not a Valid Activity Center"), but retain a record of the observation in the database. Similarly, the Service sometimes determines that a site is "permanently abandoned" (e.g., there is not sufficient quality and/or quantity of habitat to support owls now or in the foreseeable future). We change these Activity Centers to ABAN ("abandoned") status, signifying that the historic site is no longer suitable. We are working with the Service to obtain a comprehensive list of TA letters that address "not valid" and "permanently abandoned" owl sites, and these determinations should be reflected in the database soon.
- What about unoccupied sites? Shouldn't those also be labeled with ABAN?
Per U.S. Fish and Wildlife Service Technical Assistance letter 8133-2008-TA-0040 (28 May 2008): "Occupancy is an annual rate and is not equivalent to 'abandoned,' which is a permanent status." CDFW is currently working with the Service to clarify whether several sites are "unoccupied" or should be considered "permanently abandoned." These sites currently have an additional record at the AC location with "UNOC" in the AGESEX field, signifying that USFWS has considered them either unoccupied or abandoned in the past. After these issues are resolved, UNOC status will be eliminated from the database because CDFW does not receive sufficient data to track annual occupancy for owl sites throughout the state.
- Is there a way to "turn off" observations that aren't Activity Centers?
The BIOS Data Viewer allows users to display only currently active Activity Center locations by using a filter on ds704 where "TYPEOBS" = 'AC'. However, we strongly encourage users to take into account all recent owl observations in the area of interest rather than focusing solely on Activity Centers. We would also like to remind our users that CDFW does not have complete and up-to-date survey data for many locations, and a "historic" Activity Center location is not necessarily representative of current owl habitat use.
- How accurate are the owl locations in the database?
We always use the most detailed data provided to us by our contributors, but we can only be as precise as our data allow. If a map or coordinates are provided, we plot the location of the owl or the call station whenever possible; when a location represents the call station, we note this in the COMMENTS field and include the estimated distance and bearing to the owl, if provided. For "no response" surveys, the point is understood to represent the call station coordinates. In some cases, however, we only receive PLSS (Township-Range-Section) information. These observations are assigned to a point in the center of the section, half-section, or quarter-section. The method used for determining the coordinates of a record is provided in the COORDSRC field and the various methods are described in detail in the COORDSRC metadata. It is extremely important for users to consider not only the coordinates of an observation, but also the source of those coordinates. Less than 1% of the activity centers in the database have coordinates that were derived from quarter-section, half-section, or section centroids. We hope to obtain more precise location data for these Activity Centers soon. It is also important to keep in mind that there is some degree of uncertainty in the location of owls that were heard but not seen (typically during nocturnal surveys), and a quarter-section designation might be a more realistic estimate of the owl’s location than a point.
- Where do CDFW's owl data come from?
Some individuals or groups (e.g., those in possession of a scientific collecting permit for capturing and banding owls) submit their data as part of a Memorandum of Understanding with the Department. Some of our data are obtained through timber harvest plans submitted to CAL FIRE for review. A few observations have been gleaned from U.S. Fish and Wildlife Service Technical Assistance (TA) letters. However, the vast majority of observations in the database have been voluntarily provided to CDFW by other State and Federal agencies, private landowners, land managers, consultants, researchers, and field naturalists.
- My company provided observation data to CDFW quite some time ago. When will our data show up in the BIOS layer?
Due to past staffing issues, we currently have a backlog of data waiting to be entered. However, we now have a biologist working full time on the owl database and we began making regular updates in December 2012. Spotted Owl database updates are released on the first Tuesday of each month to coincide with the monthly California Native Diversity Database updates. Unfortunately, we cannot currently provide an estimated timeline for how long it will be before a specific dataset is processed, entered, and "live" in the BIOS viewer. We generally prioritize entry of more recent data and observations which might represent new Activity Centers, but we are grateful for any and all survey data. Rest assured, CDFW values your contribution and we appreciate your patience while we work through our current backlog.
- I am interested in contributing data to the database. Who should I contact?
Our Spotted Owl Database Manager would be happy to work with you to see that your observations of Northern Spotted Owls, California Spotted Owls, Barred Owls, and Strix hybrids are included in a future database update. You can email our account or reach the Database Manager at (916) 445-5006 for more details about data submission. Every observation, even an opportunistic detection or a "no response" survey, helps make the database a more valuable tool for research, conservation, and management. Thank you for your support!
- Additional questions, comments, or suggestions?
Help in understanding how the BIOS Data Viewer works is available on the BIOS website (see Getting Started in BIOS 5 (pdf) and Data Viewer Tutorials). Metadata and explanations of the fields and codes used in the Spotted Owl Database are available with the shapefiles packaged with CNDDB/RareFind or by using the Metadata button in the tool bar of the BIOS Data Viewer. For other concerns, please email our account or call our Spotted Owl Database Manager at (916) 445-5006. Check this page regularly, as it will be updated based on feedback from our users and contributors.