A black-tailed deer inspects our trail camera during daytime grazing.

Data from SPAWN’s five trail cameras reflect when our local fauna are most active. Time of concentrated activity provides information about species’ behavior. Additionally, it may help us identify unknown specimens by comparing activity patterns with known averages.

We addressed the following hypothesis: “Sightings of each species will occur unevenly throughout the day.¬†As certain species have strong diurnal or nocturnal habits, we expect appearances on trail cameras to reflect these trends.”

We describe each species with three major categories:

(1) Diurnal species are those most active during the day.

(2) Nocturnal species are those most active at night.

(3) Crepuscular species are those most active at dawn/dusk.

A fourth category of “cathemeral” may be included in future considerations. Cathemerality refers to sporadic activity throughout the day/night and may be influenced by a number of factors.

We observed the following species: bird species (except turkey), black-tailed deer, bobcat, cattle, coyote, grey fox, grey squirrel, mouse, opossum, raccoon, striped skunk, turkey, woodrat, and unknown. We plotted number of occurrences against time of day to log when certain species are more active. Other potential factors in activity (location, temperature, et cetera) were not considered.

The graphs below summarize our findings, followed by a brief discussion for each species. Diurnal species included birds, grey squirrel, and turkey. Nocturnal species included bobcat, grey fox, field mouse, raccoon, striped skunk, and woodrat. Crepuscular species included black-tailed deer, cattle, and opossum. Coyote and “unknown” were too irregular to classify as diurnal, nocturnal, or crepuscular.

Bird Species

Bird species show strong diurnal habits, perhaps with the exception of very early morning activities. Further steps might consider average daily temperatures and keying out species to help explain this deviation form diurnal habits.

Black-Tailed Deer

Black-tailed deer were active throughout the day, with spikes in activity around dawn and dusk. Further analysis is needed to determine if these patterns are statistically significant.


Bobcats seemed to avoid daylight hours, preferring nocturnal habits. A considerable percentage of observations were made at dawn and dusk, however.


Cattle appeared most active at dawn and dusk. Cattle presence is likely dependent on paddock rotations.


Coyote presence was sporadic. Other factors may affect coyote activity, such as weather and prey abundance.

Grey Fox

Grey foxes exhibit strong nocturnality.

Grey Squirrel

Grey squirrels exhibit strong diurnality.

Field Mouse

Field mice exhibit nocturnality, with some occurrences at dusk.


Opossums exhibit crepuscular traits. Sightings were infrequent and a larger database is desirable.


Raccoons seemed to avoid daylight hours, with more sightings at night than at dawn or dusk. More data is needed for an accurate depiction of peak activity.

Striped Skunk

Striped skunks seem to have a nocturnal preference.


More data is certainly needed to better describe turkey activity. The given data suggests a strong diurnal preference, however.


Woodrats avoided daylight hours, with most observations occurring at night and some observations occurring at dawn and dusk.


Unsurprisingly, the “unknown” category shows no strong pattern. This suggests that there is not one unknown species that is particularly difficult to identify, but rather that limiting factors in identification tend to be the result of poor lighting and other conditions.

Singling out time of observation as a single factor in wildlife activity is a helpful first step in understanding our fellow Marinites. Further steps include similar singular analyses for other factors (such as weather, temperature, and location), followed by multi-variable analyses. Not much is simple in the intricate workings of our lives, and we expect no less from our wild neighbors!

A coyote stalks prey in the night.