Caribou Migration Update: March 20, 1997

Each spring at this time, Robert Mulders and Dave Abernathy conduct a "composition survey" of the Qamamirjuag"(Kaminuriak) caribou herd. As you will read in Mulder's note below, they will be leaving any day. Here is his summary from last spring's survey, along with a Challenge Question for you:

"I classified a total of 13,488 caribou and found that overall there were 42 calves per 100 cows. It was interesting that in the northern portion of the migration (north of latitude 60 40) there were 26 calves: 100 cows. In the central portion of my sample (between 60 20 and 60 40 latitude) there were 37 calves: 100 cows, and to the south (between 59 45 and 60 40 latitude) about 82 calves: 100 cows. This pattern confirms that ………."
How would you complete the sentence?

Challenge Question # 6
"Why do you think there were more calves per cow in the south than in the north? What do you think this patterns confirms?"

To respond to this Challenge Question please follow the instructions at the end of this report. (Please Note: Since our report is late this week, we will wait to summarize some of the previous Challenge Questions. Thanks for all your answers!)

• Click Here for Today's Satellite Data

Keep Your Eye on # 3924
We've added new satellite data today, along with the readings from the first part of March. This way, you can see trends in their movements even without a map. As you will read in the note today from Robert Mulders (see below), he must remove collars from 3 of the caribou. Luckily we will still have 3 females to track for the rest of the season--and luckily one is a cow of particular interest. # 3924.

Gov't.of NWT, Dept. of Renewable Resources

The Question: Is Caribou #3924 part of the Beverly Herd?

Robert Mulders provides some history: "This cow was collared in early April 1995 to the NE of Neultin Lake (around 60 45 X 98 30) and was traveling eastward within a large movement of "Qamamirjuag"(Kaminuriak) caribou. We considered this area to be Qamanirjuag winter range, and were quite surprised when several days later #3924 promptly swung around to the NW and passed Dubawnt Lake on its way to the Beverly calving grounds. This cow over-wintered further west in "typical" Beverly range, and is again using the Beverely calving grounds. It's hard to say whether this was a Qamanirjuag caribou which switched herds, or whether this is a Beverly caribou which just happened to briefly get caught up with the wrong crowd last year. This issue of herd intermixing and female fidelity to calving grounds is an important management question. Telemetry studies on Qamanirjuag caribou in the mid-1980's suggested that about 3% of cows were not faithful to their previous calving grounds."

Which calving grounds do you suppose she will go to this spring? Keep a close eye on her movements over the next weeks.

Here's today's note from Robert Mulders. These spring field trips can be an adventure! We hope to have interesting news to report when the biologists return. You can read about last spring's trip.

"Dave and I have been in limbo this week since we still don't have a firm commitment for a helicopter. Once it arrives, however, we will immediately be heading out to remove collars: 6978, 6980 & 3925. We'll stay at a small cabin at Sealhole Lake (60.47N, 98.47W) which is at the NE end of Neultin Lake.

"You asked how we will recapture the caribou. Each satellite collared female also has a radio transmitter with its own unique frequency. As we get within 20 miles (32 km) of the collar, our radio receiver picks up the signals. Signal strength gets stronger as we approach the collared individual., and we have to visually spot the collar from a group of perhaps several hundred caribou. From the helicopter we'll use a special 20' x 20' net, projected from a net gun to capture the collared caribou. Once the collar is removed the caribou is set free.

"At this of time of year the caribou hides are fairly white, caused primarily by the bleaching action of the bright sun and glare off the snow surface. Depending on the winter range conditions (i.e. snow depth), and the fat reserves used during the spring migration, some caribou may be getting a bit thin. As the snow starts to melt, their range (food supply) is exposed and caribou begin to restore their fat reserves."

How to Respond to Journey North Caribou Challenge Question # 6

1. Address an e-mail message to: jn-challenge-caribou@learner.org
2. In the Subject Line of your message write: Challenge Question # 6
3. In the body of the message, give your answer to this question:

Challenge Question # 6
"Why do you think there were more calves per cow in the south than in the north? What do you think this patterns confirms?"

Don't Forget!
Please include the name of your school and your location so we can credit you properly for your answers.

The Next Caribou Update Will be Posted on April 3, 1997.