Volunteers arrive, two-by-two, every night for one week to monitor closely Mei Xiang and Tian Tian and record what they're up to -- or in some cases, not up to.
The night watch is historic because it is identical to the study conducted at the panda exhibit here 29 years ago when Ling-Ling and Hsing-Hsing were the residents of the panda exhibit. The data collected will be used to make comparisons amongst the four pandas to see if our panda couple in 2001 act any differently at night than Ling-Ling or Hsing-Hsing did in 1972.
When the night watch concludes, behaviorists will begin tabulating
the data they need to begin to draw conclusions. Both pandas
are watched simultaneously by two people who record the behaviors
of each animal. Start and stop times are written down for
rest/sleep, eating/drinking, grooming, bathing, scent marking,
urination/defecation, or a catch-all of "other" in which volunteers record rolling or anything else that doesn't
fit into the other categories. Also recorded is the exact
location of the indoor habitat of each panda throughout the
night. Scientists will be able to tell what proportion of
time is spent on their rocky substrate versus the floor.

Friends of the National Zoo volunteers who had not previously participated in Zoo research projects attended a three-hour "Historic Night Watch" training to prepare for their jobs. David Powell, postdoctoral scientist, giant panda behavior studies, played videotape of panda behaviors to show volunteers what to look for. That way, they could more easily recognize, differentiate, and record some of the subtle behaviors, like the difference between the squat posture and the hand stand when scent-marking. So far, Mei Xiang and Tian Tian have only been seen scent-marking in the squat posture, so perhaps a new technique will be seen for the first time this week.
To ensure that comparisons are valid, duplicating as closely as possible the original study conducted with Ling-Ling and Hsing-Hsing in 1972 is a top priority. It helps having Nell Ball, a volunteer who participated in a previous night watch, train less experienced volunteers and share specifics about how details were recorded.