We now have a Twitter feed! Please follow us @KJRScience for more photos, news and #IslandLife shenanigans!
The first week of our stay on the Isle of May grey seal breeding colony has flown by, and the number of mother – pup pairs is growing daily. The PHATS team from Abertay University and the Sea Mammal Research Unit, University of St Andrews is still waiting for our first sampling opportunity before we can start work, looking at persistant organic pollutants (POPs) and how they affect fat tissue function in seals. We will get the chance to start our sample collection in about a week, when the pups are almost ready to wean from their mothers and are large and fat (see the previous blog for more details about our sampling regime). While we wait both Holly and I are helping survey the colony regularly by doing observations of the seals arriving and looking to see if any seals are study individuals. Study individuals are females that have been included in the Isle of May grey seal research project for many years, and they usually have small flipper tags to help us identify them. Female grey seals typically come back to the same colony to give birth, and as they have spotty patterns on their fur that stay the same throughout their lives, we can identify the same females year after year and build up long term datasets of what happened to them across many years.
All the other research projects on the Isle of May are in full swing, as they are interested in the seals from when the pups are born right through to weaning. For example, Dr Sean Twiss is leading a team here from Durham University studying the maternal behaviour of grey seals and how it can be linked to physiological metrics like heart rate data from novel, external loggers they designed and built themselves (read more about their research here). There is always plenty going on to observe in the colony, never a dull moment! Here are a few of the behaviours you can see currently on the Isle of May breeding colony:
Grey seal births are extremely rapid and can be tricky to see. After the birth, mothers will sniff their pup and bond with it so they can stay together for the coming weeks on the busy colony. Newborn pups are pretty easy to spot as the mothers can be quite red from the blood lost during delivery and sea gulls come to scavenge the placenta to eat. Seal mothers do not always react well to this, and can spend lots of time chasing gulls away from themselves, their pup and the placenta. My PhD work was primarily on maternal behaviour and how mother-pup bonds form, and I always love watching births if I can spot one.
Grey seal mothers only spend about 18 days with their pups before weaning them and going back to sea. In those 18 days it is vital for the pup to drink as much fat rich milk from the mother as possible, the larger a pup is at weaning the more likely it is to survive its first year of life. Grey seal milk is 60% fat so pups can put on weight very quickly, pups born at 18kg can easily reach more than 50kg in just over two weeks! Nursing bouts take about five minutes and happen approximately ever four hours throughout the day and night.
Defending the pup from other seals and gulls
A grey seal mother will aggressively defend her pup from anything that approaches too closely. Other female seals will attack any pup that is not their own and males will not tolerate pups in their personal space either. Without their mothers to defend them, pups soon become covered in bites from other adults. Sea gulls can also seriously injure, and in some cases kill, grey seal pups by pecking at their eyes and fresh umbilical. Mothers therefore do not tolerate gulls coming to close and will aggressively chase them away.
Male dominance fights
As the breeding season progresses, more male grey seals arrive on the colony to try and hold a position among the females, so that they can try to mate with them once the pups are raised. Males will threaten each other with hisses and open mouth threat displays, but many confrontations do not result in fights as these are dangerous and tiring for both parties. Sometimes however, neither male will back down and the two will fight brutal battles for dominance, biting and shaking each other’s necks and heads.
MEANWHILE away from the seals, the team on the Isle of May are enjoying island life as much as possible. The sunrises here are stunning and there are lots of amazing birds flying around to watch out for, the short eared owls are a particular favourite currently. Half of the team indulged in a rare TV night to join the rest of the nation in watching the Great British
Bake Off final, and as that put me in a baking mood I made some coffee and walnut cupcakes for everyone. We were joined yesterday by the leader of the PHATS team, Dr Kimberley Bennett fresh from teaching at Abertay University and she brought some fresh food supplies, even more lab gear and halloween goodies! Cue some epic pumpkin carving by Holly and fellow research assistant Izzy, now to put them somewhere high so the mice don’t attack them in the night!