Here's what he wrote:
"We have already carried out a couple of early morning reccies and have seen eight male black grouse on the lek. As expected, they were behaving very aggressively towards each other as they vied for the centre spot hoping to catch the eye of a passing female.
"On one occasion they all flew off into the thicker heather and it wasn't long before we found out why. A female hen harrier came low over the horizon quartering the lek where the grouse had been. After about 20 minutes the grouse must have sensed the all-clear and returned to the lek to carry on displaying.
After all, what's a bit of danger when there's a chance of making whoopee?
"We also visited the hide at dusk one evening. We were a bit disappointed to see only one male on the lek and even it was keeping its head down.
"However, on further inspection we spotted several other males busy feeding in the cleared areas of heather.
"This proves two things. One - cutting the heather is providing valuable food for the grouse. And two - food is more important than sex!"
Want to know more?
If you fancy joining Des or one of his colleagues on a black grouse lek, you can get all the information you need on the RSPB website.
And remember to let us know how you get on. You can post a message using the comment form below.