FAQs

• Where did the black pouch in every photo go?
• Why is there only one photo rather than a sequence of photos?
• How can I gauge scale in a photo?
• How should I tag photos with vehicles?
• Why are there empty photos?
• How do I use hashtags?
• Why is there no “unknown” button?
• Why are there photos of humans?

Where did the black pouch in every photo go?

Historically, to possibly increase our detection rates, we used scent lures that are enclosed in a mesh pouch and nailed to a tree/stump/fencepost opposite the camera. This lure could attract animals that are already nearby to walk directly in front of the camera. Even with a lure, our data indicate that the probability of detecting these mammals is roughly 10-20% per day if they are present at a site. However, since about season 15 we stopped using these lures! While we thought the lures increased the probability of detecting our urban mammals, we later found out that is barely had an effect (and possibly lowered the detectability of prey species). As a result, we made the informed decision to stop using lure, and are still getting lots of animals in front of our cameras.

Why is there only one photo rather than a sequence of photos?

Because this is a long-term study that amasses >30, 000 photos per season, we have chosen to set our cameras to take only one photo every 30 seconds (if there is continuous movement). We realize that this makes it a bit more difficult to classify the photos but we know our volunteers are up to the challenge!

How can I gauge scale in a photo?

Understanding the size of an animal relative to the landscape can be tricky, but there are a few tricks you can use. Comparing the animal to the relative size of tree trunks visible in the photo also can be useful. Finally, the camera itself is typically placed at a height of 4 - 6 feet (1 – 2 m) off of the ground. If you come across a photo where the animal is directly in front of the camera, it is likely a deer, as these are the only animals in our area that are tall enough to reach the camera lens.

This is likely a photo of a deer given the proximity of the animal to the camera.

How should I tag photos with vehicles?

Occasionally a camera is pointed toward a road and we see photos of vehicles. Please enter these photos as “nothing here”. In the past, vehicles were not entered consistently, and are often on the street surrounding a site, not present on the site itself. The one exception is a riding mower. Because our sites include parks with turfgrass, lawnmowers can be seen regularly at some cameras. Identifying the frequency of mowers helps us to understand the impact of human activity on wildlife in this urban habitat.

Why are there empty photos?

There are several reasons for empty photos. Cameras can be triggered by moving leaves, grass, or tree branches, or can just simply malfunction. It’s likely that in some cases an animal triggers the camera, but it moves out of frame before the picture is taken. Before we upload the dataset, we remove photos from cameras that have clearly malfunctioned. Before you click “nothing here” be sure to look very closely! Something might be hiding in a corner.

How do I use hashtags?

Hashtags can be added to a photo after classification by clicking “Done and Talk” and entering a hashtag in the comment section for that photo. We encourage the use of hashtags when you are certain about the species classification. This provides an excellent learning tool for other volunteers who may want to see examples of a certain species. You are welcome to hashtag other observations about the photos (e.g., “cute”) but please refrain from hashtagging anything inappropriate (see below for hashtags on Human photos).

Why is there no “unknown” button?

Snapshot Serengeti has a great explanation in this blog post. In short, if we are forced to make a guess, there’s a good chance that we will be correct! In addition, several people see each photo before it gets retired and we consider the response of the group. We realize it can be frustrating, but even those impossible-to-ID -photos are helpful data! Please check our field guide for tips on how to ID the tough species. If you want some expert feedback, use the hashtag #whatis in the Talk section and we will do our best to help!

Why are there photos of humans?

Because we are placing cameras in public places, we do occasionally get photos of humans. Once a photo is identified as having a human, the photo is immediately removed from the classification pool for privacy considerations. Please do not Talk about, hashtag, or collect these photos; they will be deleted from Talk immediately.