- 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information than the reports from the older (and now outdated) Spotted Owl Territories layer (ds97).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
Spotted Owl 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
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
Spotted Owl 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.