'Secrets of Our Living Planet' continues on Sunday 7pm on BBC2.
This time Chris travels to North America to witness the annual miracle of the temperate forest: the destruction of its ecosystem in winter, followed by it rebuilding itself in spring. Chris marvels at the exquisite timing that is necessary in two particularly wonderful stories - the story of how the Canada lynx depends for its prey on a caterpillar high up in the canopy, and the story of why the giant trees of the north-west are dependent on bears and salmon.
Here's my account of filming and getting close to grizzly bears in British Columbia.
On the west coast of Canada lies the Great Bear Rainforest, spreading for 70,000 square kilometres. Here, grizzly bears gather along waterways, as millions of salmon make their autumn migration upstream to spawn. This is the best time of year to see grizzly bears and certainly our best chance of filming them.
Cameraman Mark Payne-Gill and I about to fly out to the Great Bear Rainforest
Cameraman Mark Payne-Gill and I worked with local expert Tom Rivest to identify key spots for filming. We were looking for riffles, where the water was shallow enough for the salmon to spawn, and where the bears could easily catch fish.
Once we had a spot, we hid amongst the vegetation on the bank and waited. The rain poured heavily. Salmon splashed in their thousands, strenuously fighting the flow to head upstream. Some spawned amongst the riffles, whilst others, having spent their energy, simply rolled over and died. Bald eagles were making the most of the banquet, and much to our surprise - it didn’t take long for a bear to appear.
Once we had a spot, we hid amongst the vegetation on the bank and waited. The rain poured heavily. Salmon splashed in their thousands, strenuously fighting the flow to head upstream. Some spawned amongst the riffles, whilst others, having spent their energy, simply rolled over and died. Bald eagles were making the most of the banquet, and much to our surprise - it didn’t take long for a bear to appear.
The feast arrives
A mother with three cubs cautiously approached the water’s edge, keeping a lookout for dominant male bears who would likely kill her cubs on sight.
With the coast clear, mum wasted no time and jumped straight into the river to catch fish, leaving her cubs on the bank to dig for salmon eggs. It was thrilling to be less than 40 metres away from her as she crashed powerfully through the water to chase salmon. She then greedily scoffed it right in front of us.
Bears prefer to eat the fattiest parts of the fish, the brain and the ovaries packed with eggs – giving them maximum calories per bite. This selective feeding helps them to quickly fatten up ready for hibernation.
By consuming as much as 60,000 calories a day, the equivalent of 500 chocolate bars, grizzly bears can almost double their body weight in just a few weeks, and by my count that bear had eaten at least 20 salmon in just one session!
For every salmon she devoured, she would carry another back to the bank for her cubs. Occasionally she glanced in our direction and sniffed before taking another bite.
By consuming as much as 60,000 calories a day, the equivalent of 500 chocolate bars, grizzly bears can almost double their body weight in just a few weeks, and by my count that bear had eaten at least 20 salmon in just one session!
For every salmon she devoured, she would carry another back to the bank for her cubs. Occasionally she glanced in our direction and sniffed before taking another bite.
Mum keeps a watch out as her cubs feed on her latest catch
Bear cub takes a look up from digging for salmon eggs (there's one on his nose!)
Taking a break from fishing
It wasn’t long before an adult male approached to take over these prime fishing grounds. The danger posed by these males is a key factor in what makes bears and salmon so important to the health of the forest. The danger forces subordinate bears, and females with cubs, to leave the river and head for the safety of the trees - and as they do they take the salmon with them.
A mob of more mature bears can pose a threat to young cubs
After feasting on the fattiest parts of the fish, the bears dump the rest on the forest floor. So many bears feed here that an area the size of a football field can have as much as three tonnes of salmon, giving the place a distinctly fishy smell. This is when the magic happens because when the fish rots, it releases a huge amount of carbon and nitrogen into the soil, and these vital nutrients help the trees to grow.
Over the next few days, the bears were as regular as clock-work and turned up for breakfast at around 8:30am and then again for dinner at 5pm. My guess is that they spent the middle of the day asleep, in the forest digesting.
Too close to film! We take a break as a grizzly snacks on a salmon below our hide
Over the next few days, the bears were as regular as clock-work and turned up for breakfast at around 8:30am and then again for dinner at 5pm. My guess is that they spent the middle of the day asleep, in the forest digesting.
Close encounter in the forest
During our explorations through the forest we discovered some fresh bear beds – padded down dig outs surrounded by lots of fish scraps. With the river level continuing to rise, the salmon were becoming more difficult to catch and Tom told me that the bears would start spending more time in the forest polishing off the scraps that they’d left behind.
This would be an ideal spot to get shots of bears amongst the trees but it would be dangerous to film here within the enclosed confines of the forest, and so we turned to technology.
While the bears were out fishing in the morning we snuck in and setup various motion triggered cameras. We had to act fast. Bears could be anywhere and there were around 40 in this one small valley!
I was attaching a camera to a tree, when I heard a rustle. I thought it was Mark the cameraman until I heard a grunt. I turned around to see a large female bear less than 10 metres away and a cub close behind.
Her hungry eyes locked on me. Was I a healthy alternative to fish scraps or a threat to her cub? Either way, she was certainly surprised, and a surprised bear is a dangerous one. The hairs stuck up on the back of my neck, my heart sank. Instinct told me to run, but my training taught me that the best way to respond is to keep calm and talk to the bear. With Tom calmly standing by, I said ‘Hey bear... sorry for trespassing on your forest’.
Thankfully, the bear understood my British accent and headed back to the river. I switched the camera on and we got out of there.
While the bears were out fishing in the morning we snuck in and setup various motion triggered cameras. We had to act fast. Bears could be anywhere and there were around 40 in this one small valley!
I was attaching a camera to a tree, when I heard a rustle. I thought it was Mark the cameraman until I heard a grunt. I turned around to see a large female bear less than 10 metres away and a cub close behind.
Her hungry eyes locked on me. Was I a healthy alternative to fish scraps or a threat to her cub? Either way, she was certainly surprised, and a surprised bear is a dangerous one. The hairs stuck up on the back of my neck, my heart sank. Instinct told me to run, but my training taught me that the best way to respond is to keep calm and talk to the bear. With Tom calmly standing by, I said ‘Hey bear... sorry for trespassing on your forest’.
Thankfully, the bear understood my British accent and headed back to the river. I switched the camera on and we got out of there.
The river rises
More than 15 inches of rain poured over the next few days, and the river rose by an incredible 10 metres – extreme even for the rain coast! With fresh salmon now out of reach, the bears were leaving the river’s edge and we were encountering them more and more along the forest trails.
The rising water level makes it a real challenge for bears to catch fish
We were filming a waterfall, when behind us a bear powered its way out of the undergrowth. Dripping with rain, she stood glaring amongst the damp mossy backdrop. She was less than 5 metres away and I could smell her fishy breath.
Tom did his usual calm talking, ‘Hey bear’, and Mark carried on getting the shot. By the time Mark turned around, Tom had worked his charms and all Mark saw was a big wobbling backside sauntering down the trail. Only later did I tell him just how close we had been.
Tom did his usual calm talking, ‘Hey bear’, and Mark carried on getting the shot. By the time Mark turned around, Tom had worked his charms and all Mark saw was a big wobbling backside sauntering down the trail. Only later did I tell him just how close we had been.
The next day, we were trapped in our little floating house on the estuary. Even the access road through the forest was deep underwater. It poured with rain for seven days straight, and we barely left our cabins.
Getting Drenched in the Great Bear Rainforest
Getting Drenched in the Great Bear Rainforest
Why the forest needs the salmon
This huge volume of rain is what makes the salmon so crucial for the forest. All this water continually flushes nutrients out of the soil and into the rivers. This helps to nourish aquatic plants and salmons’ eggs but leaves the forest relatively impoverished.
Eventually the young salmon head out to sea, but when they return to spawn, the bears will be waiting. In turn, they will carry the salmon nutrients back into the forest which will help to keep the whole system in check.
Finally the rain stopped and the river level dropped, allowing the bears to continue their autumn feast and leaving us to get the footage we needed.