The last couple of days have been a wee bit blowy, and a bit moist! It all makes doing observations a little more challenging, especially trying to keep the video cameras we use from drowning in the rain! But, its great weather for seals. Breeding grey seals love to have some water around, and not just for splashing around in, but also for drinking (though the pools they drink from a typically pretty murky!)
Over many years of working on grey seal breeding colonies, what is apparent is that long term changes in weather patterns during the autumn are changing the seals behaviour markedly. Much of our research has focused on this aspect, and despite breeding in the autumn, with the high energy demands of raising a pup, and starting the season with a thick (approx. 5cm) layer of blubber to provide that energy, grey seal mothers breeding in the UK in the autumn are thermally stressed – they get too hot! So, they need access to pools of water for cooling down and drinking. I was also studying seals on the Isle of May back in the early 1990’s, and things have definitely changed. Yes, there are more seals on the island, but also the weather is generally much milder and dryer. This impacts on the seals’ behaviour – mothers regularly leave their pups to seek pools of water to cool down in. Traversing through a busy colony has its hazards – usually involving lots of aggro with other seals en-route. Amazingly, some mothers seem to know the lay of the land in remarkable detail, and will take quite circuitous routes, avoiding other seals, to get to a pool that is well out of sight of where they have their pup. Mums eventually return to nurse their pup, after cooling down in pools. This ‘commuting’ behaviour is clearly more evident on hotter sunnier days – hence why rainy days seem to make life on the colony easier for the seals, if not for us!
Again, our work with the heart rate monitors will help here – telling us how much more stressful for seals hotter days are!