Category Archives: Harbour Seals

Missing 2020 fieldwork

We have been very quiet since our last post at the end of the 2019 season. Unfortunately our 2020 fieldwork had to be cancelled with the COVID-19 pandemic, which means we will have a one year gap in our time-series. It has been very strange not to pack up cameras and tripods and head to Orkney, Kintyre and Isle of Skye this summer. We have no idea which of the known seals have been there, or who has had pups this year! What a strange feeling!

Despite the lack of fieldwork and the general silence in the blog we have indeed been very busy behind doors, primarily processing and analysing data. We spent the autumn and winter of 2019 going through all the photographs collected during the summer of 2019, matching them to the catalogues of seals at each site and adding new seals if we could not recognize them.

Harbour seals in Loch Dunvegan in late July showing some of the pups born in 2019 (photo by Helen Hiley)

The pictures taken in Orkney were the quickest to be processed, for two main reasons. First, we have had the same person taking the photographs and identifying the seals over 4 years, and in the world of manual identification of seals, experience counts a lot! One ends up recognizing the seals in the field already, making the processing of photographs in the computer a much easier job. The other contributing factor is that the number of seals that we see every year in Orkney has been declining, a reflection of the continuous decline in numbers of harbour seals in this area. At the end of the day that means less seals to be identified…

Or012, photographed in July 2019 in Orkney. We have known this seal since 2015 (photo by Mònica Arso Civil)

The hardest of all our study sites is still Isle of Skye. Despite going out to take photographs less often than in Kintyre or Orkney, the number of seals hauling out in the skerries near Dunvegan Castle in Loch Dunvegan is so large that the task of identifying them is much more challenging. We have over 600 seals in the catalogue for Loch Dunvegan, way more than in any other area! That means that the chances of mistakenly identifying two seals as the same one or giving the same seal two different IDs are much higher. That is particularly the case for those seals with very pale pelages, such as the ones below. Luckily we have a super team working on it who have become very good at knowning these Loch Dunvegan seals.

Alongside the photo-ID processing we have also been analysing some of the other data collected over the last 4 years. We recently published a paper where we showed how to determine pregnancy in harbour seals based on the levels of progesterone in their blood and blubber. The study was led by Prof Ailsa Hall in collaboration with colleagues at the University of Aberdeen Lighthouse Field Station and was publised in the Jounal of General and Comparative Endocrinology. In a nutshell, we analysed blood and blubber samples taken sometime between February and May (so before harbour seals have their pups, which is around mid to end June), to look at the levels of progesterone. Progesterone is one of the hormones produced during pregnancy, when it can be found in much higher concentrations, especially towards the end of the pregnancy. So by looking at the levels of progesterone, we can estimate if a female is likely to be pregnant or not (similar to running a pregnancy test). Some of the females we sampled were also photographed during the following pupping season, which means we could see if they were indeed pregnant (although that is not always obvious) and/or if they gave birth to a pup. By putting those two pieces of information together and knowing the fate of some of the potential pregnancies, we could establish thresholds of progesterone concentrations above which harbour seals are pregnant. Using those thresholds we then calculated how many of the captured adult females were likely at each of the study sites (Orkney, Isle of Skye and Moray Firth). We found out that the proportion of pregnant adult females was high across sites (63%-100%) and were not statistically different from each other.

Or085 pregnant (see the extented round belly) (photo by Mònica Arso Civil)

Or085 checking on her new pup (photo by Mònica Arso Civil)

The team is working hard to finish off the Skye 2019 data and some other lose ends with the photographs. Once that is done we will start using the data to estimate birth and natural mortality rates of harbour seals at sites that have shown different population trajectories over the last couple of decades.

Keep tuned!

Goodbyes to Orkney

Last monday I said my goodbyes to Orkney, as I took the Pentalina ferry from St Margaret’s Hope to Gills Bay one last time. After 4 summers spent in Orkney collecting photo-ID data on the harbour seals in Widewall Bay and Burray, it was time for me to pack my bags and head down to St Andrews. This last season is not quite finished, but I have left in the capable hands of my colleague Emily, who will take over for what’s left of this month of July. By the end of it, most of the pups will be weaned and juveniles and adults will be ready to start or will already be well into their annual moult.

Beautiful morning for a sail to mainland…

The ferry happens to go past one of the monitored haulout sites… last opportunity to say goodbye to the seals!

The last day I went out to get data on my own was on a friday, and what a beautiful day that was! The sun was shining and it felt like proper summer! Luckily it was early enough in the day that it was still cool and not too hazy, otherwise it is really tricky to get photographs of the seals that are actually in focus! Another challenge of these hot and calm days, especially when the tides are not very big, is that the seals will generally not move AT ALL. And when I mean not at all, I mean a seal will be in the same position, belly up and not lifting her head up even once. They can be in the same position for the 3 hours one is observing and trying to get pictures. It is not very convenient for us but highly convenient for the seals, that’s for sure!

Cracking day in Widewall Bay

Or075 and her pup having a snooze. Check how calm the water is below them!

Really quiet days come with little disturbance from weather elements, which means any other sound will be heard by the seals and it has the potential to wake them up. On that day, there were some Eider ducklings at the haulout site in Widewall Bay, and any time they made some noise they managed to wake up a couple of sleeping seals, which got a proper startle!

Eider duck with her ducklings

 

That last day I managed to visit all three main sites, photographing a large proportion of the seals resting (yes, some of them were asleep and impossible to photograph). By this time in the season, the juveniles are looking very ready to moult, looking uniformly brown and feeling itchy… If it gets too hot but you don’t want to get into the water completely, you might as well just dip your head in…

Juvenile harbour seal cooling off by dipping its head in the water…

The pups that were born first are now about 4 weeks old, and probably close to being weaned. They have gone from being a bag of skin and bones with little blubber to big round balls of fat. The lactation period might seem short (about 24 days; Bowen et al. 1992, 2001) compared to other mammals, but it is highly efficient and intense, as harbour seals secrete large volumes of energy-dense milk with 40-60% fat. Female harbour seals do not have enough body energy stores to fast throughout the  lactation period. To make up for the energetic cost of lactation, females will forage during that time, starting with short foraging trips lasting only a few hours about a week after giving birth.

Or062 and her pup, also a female, looking very big by now…

Through this project we have been able to gather information on individual seals over 4 separate summers. This longitudinal individual data is key to figure out population dynamics questions, which is the same as saying we are trying to answer questions about what is causing the numbers of harbour seals to go up or down in different areas. Are there not enough pups being born? Are these pups surviving as one would expect for a seal? What about the juveniles or the adults? Or are there any differences between males and females? We might not have enough data to answer all these questions given the length of the study (4 summers is not much compared to how long seals live), and the limitations of following pups onto adulthood, but we are hoping to be able to answer some of them.

There are other interesting facts associated with the data we collect. We can see, for example, differences in how females succeed at pupping every summer. Some will pup earlier than others in the season, some will not pup in a given year, some will not manage to wean a healthy pup while others end up weaning pups that are bigger then the one-year-olds.

Or094 with a pup in 2016, 2017 and 2018, but on her own in 2019

As an example, below are two photographs of Or118 and her pup from this year. The time difference between the photographs is 3 weeks. And check how much bigger the pup is by then!

Or118 and pup on 21st June, about 2 days after being born

Or118 and pup on 13th July. Look at the difference in size in those 3 weeks!!!

Four summers of observing the same seals has other rewards, as one gets “to know” the different individuals. By this I mean not only learning to recognize them in the field but also noticing that different seals do different things, and these differences in behaviour sometimes repeat across years. Some seals seem to have favorite spots to haulout, as they will repeatedly be found in that elevated rock, day after day and year after year, like Or057 in the picture below. Different seals are more or less tolerant to having other seals nearby, and females might be more or less patient with approaching pups.

Or057 in one of her favourite rocks, year after year…

In a way that does help to collect data every summer because one can kind of predict what certain seals might do next. There are some behaviours that generally apply to all seals too. For example, seals do not like heavy rain (who would have thought?), and will slowly (or not so slowly) leave the haulout site and return to the water if there is too much rain. Also, seals will tend to follow a pattern of movements within the haulout site at different times of the tide, and depending on how close to neap or ebb tides it is in the cycle. When females come out of the water with a pup, there is a short window of opportunity to get the photographs done, as the female will position herself quickly for the pup to suckle but then will lay with her head down and thus will make it impossible to get a picture.

I am taking with me all of this knowledge and fieldwork memories, which I am sure will remain with me for a long time. Now, however, it is time for some office work to deal with photograph processing and analysis. Let the fun bit begin!

Written by Monica

References

Bowen, W.D., Oftedal, O.T., and Boness, D.J. 1992. Mass and en-ergy transfer during lactation in a small phocid, the harbor seal(Phoca vitulina). Physiol. Zool.65: 844–866

Bowen, W.D., Iverson, S.J., Boness, D.J., and Oftedal, O.T. 2001.Foraging effort, food intake and lactation performance depend onmaternal mass in a small phocid seal. Funct. Ecol.15: 325–334

Pupping season rapidly progressing in Orkney

Out of the three study sites (Kintyre, Isle of Skye and Orkney), Orkney is the one in which the pups arrive the earliest, normally by mid June. Consequently, it also tends to be the site in which most, if not all pups, will have been born sometime by the start of July. Because this is our 4th season in Orkney and I have been working on matching seals from this area for a few years, I do by now have a very good knowledge of the seals that are found at the monitored sites here. It also helps that the haulout sites themselves are not massive in numbers, making the catalogue of seals under 200 animals for this area. This is not the case in our study site in Isle of Skye, Loch Dunvegan, for which the catalogue currently holds over 500 seals.

Size of catalogues of identified seals in Kintyre, Orkney and Isle of Skye. The orange bars indicate the number of catalogued seals for each side (Front, Left and Right sides of the head), and the blue bars are those that might be new to the catalogue and are yet to be assigned a number if agreed these are indeed new individuals.

The advantage of recognizing the seals is that we can identify them on the spot as we collect the data in the field, which is very safisfying. Every photograph that gets taken in the field is subsequently entered in an excel data table, so that we can store the metadata associated with each photograph. Each photograph will be graded for its quality, and we will make a note if what we can see is the right, the left or the front side of the seal’s head. That is because the pattern will be different on each side, so technically we end up with three different catalogues.

We always try to get the left, front and right sides of each seal, as shown with Or118 here. It’s not always the case though!

We will also note whether the seal is associated with a pup or not, and whether we can see the pup in the photograph or if it is suckling. Other relevant information that will be noted is if we can see a seal is pregnant, if we can sex the individual or if there are any significant or unusual injuries.

Keeping track of who is at the haulout sites on a daily basis means we can monitor in situ not only who is present that season, but also which females are likely to be pregnant and which ones are having pups and when. The first pup arrived on June 12th in Widewall Bay (South Ronaldsay), belonging to female Or075. The last one was on July 1st, from Or026 (aka Pirate), who, coincidentally, was also the last female to pup last year.

Or075 with her pup on June 12th. This female was still pregnant on June 10th.

Or075 with her much bigger pup on July 7th

Or026 (aka Pirate) looking very pregnant on June 30th

Or026 with her pup on July 7th. Note that the pup has a very distinct white mark behind the left ear, which should make it easy to identify it through the season.

The pups are rapidly gaining weight with the fat-rich milk from their mothers. In just a couple of weeks from now most of the pups will be weaned, especially those born earlier in the season.

Milk moustache from Or062’s pup

Look at the size of these pups! Nothing like what they looked like when born.

As days go, the females will undertake foraging trips during lactation, to support its energetic costs. The pups will accompany them in many of those occasions, but they will also stay behind and wait for their return on shore. Some pups can be seen resting, while others will spend time in the water, or will be checking on other females and other pups, sometimes calling out. When the females return, they will look for their pups, checking on any sleeping pup around until they find theirs.

On July 8th, I spotted female Or007 approaching a haulout site from the water. She can be easily recognized from the distance because she has some scarring around the neck from some debris that got entangled around her neck sometime in the past. There is no debris left now, just a scar. This haulout site is pretty small, normally holding around 10 to 20 seals maximum. On arrival, Or007 first headed towards a mum pup pair, Or044 (aka “Butterfly”) and her pup, and checked on the pup.

Or007 checking on Or044’s pup… not her pup…

Not recognizing it as her pup, she then went on to check on another mum pup pair, this time Or135 and her pup. Wrong pup again… although the pup was quite interested and had intentions to follow this different seal into the water!

Then checking on Or135’s pup… wrong again!

Then she went onto checking a sleeping pup nearby and … hurray! Third time lucky as she finally found her pup, who was just snoozing, completely unaware of what was going on. After some nose-to-nose interaction, mum positioned herself so that the pup could suckle.

Or007 finally re-uniting with her pup!

Or007 with her pup suckling

And here is a short video of Or007 looking for her pup on that day:

The following day, July 8th, Or007 must have gone again on a foraging trip, as I spotted her pup on a nearby haulout site having a rest after checking the seals that were around.

Or007’s pup settling for a rest at the haulout site

For the next three weeks we will keep on monitoring the mum pup pairs at the haulout sites. A part from those, there are also juveniles, adult males and adult females that have not had a pup this year. The data we collect on them (i.e. whether they are present or not) will help us learn more about the mortality rates in different study sites, to see what might be behind the contrasting trajectories in harbour seal numbers in different areas of Scotland.

Written by Monica

The field season in Kintyre has begun!

So the field season is well underway in Kintyre! So far three weeks of surveys have been undertaken to photograph individual harbour seals utilising sites around the peninsula.

It’s off to a brilliant start, with lots of cloudy days which is actually the best weather for field work! Ideally, we would like a little bit of sun every now and then (it is summer after all!). However, cloudy days produce the best photographs as there is minimal glare and haze which can otherwise make photographs blurry. In addition, if a seal has recently hauled out, and the pelage is wet, on a sunny day the light reflecting off the wet coat can make it harder to get a clear photo of the pelage pattern for photo-ID.

A gorgeous harbour seal photographed on a calm day at Southend

So far we’ve had no pups yet, but we have multiple pregnant females at some of the haul out sites, and we’re expecting the arrival of pups very soon! We also have quite a few males around the haul out sites, with a few juveniles up to their usual antics. Juveniles can be seen ‘porpoising’, a form of play in which they jump out of the water like a harbour porpoise (I have yet to capture this on camera!). Juveniles are smaller than full adults, and can have a lighter coloured pelage. They also tend to be more playful in the water too.

A curious juvenile photographed at Southend

My favourite seal is ‘Goggles’, photographed below at Southend on 8th June. He is a beautiful male, and is named for his very distinctive pelage pattern. He posed very nicely on this day to get some wonderful, clear photographs of each side for photo-ID. He was seen again on 16th June, also at Southend, but this time you can see how the pelage can look slightly darker because it is wet. However, we can still identify that it is the same male based on the pattern of his spots.

Pictured above is Goggles, hauled out at Southend, and showing his left side with his distinctive ‘goggle’ pattern, and front side below.

This is Goggles on a different day sighting, this time he has a wet pelage, however is still identifiable from his unique spot pattern

It’s a tiring life being a seal; an adult male is photographed here at Yellow Rock.

Not seal-related, but we have had other stunning wildlife make some appearances too. So far this season in Kintyre, there have been three sightings of otters, including one of a mum and pup at Yellow Rock, and two sightings of a pair at Southend. In addition, there have been sightings of mergansers, shelducks, ospreys, lots of oystercatchers and the occasional sighting of the elusive caravan park cats!

I was very lucky to photograph these two beautiful otters feeding at Southend!

As well as the harbour seals, we also have Atlantic grey seals utilising the same haul out sites. The grey seals look quite different to the harbour seals up close. I always describe them as having more of a ‘labrador-like’ face, with a more prominent snout, compared to harbours with more of a ‘cat-like face’. Grey seals also have much larger spot patterns too, as you can see in the photographs.

A grey seal enjoying the sun! They have much larger spot patterns than harbour seals, and have a more pronounced snout.

We’re looking forward to the imminent arrival of pups soon, and hopefully we continue to have many more exciting wildlife sightings this season!

Abigail using a digiscope to take photographs of harbour seals at Muller South, one of our Kintyre haul out sites.

Written by Abi

 

Harbour seal birth

The last week has been pretty hectic in Orkney, with more females having their pups. In general I tend to see the pups once they are already born, and normally manage to miss the births. The main reason is that the haulout sites we monitor in Orkney are your typical haul out site in Scotland: a bit of the coast that gets exposed at low tide, covered in sea weed and rocks, rather than a sandy beach. The observation points we have chosen that get us close enough to the seals without disturbing them are on the ground level, so we do not always get a full view of a seal, as there is always a rock or bit of ground with seaweed in front.

A couple of weeks ago I was working on the afternoon and evening low tides, knowing that, at some point, I would have to switch to the early morning tide. I finally decided to do so on June 20th, setting my alarm to 5:40 am, which is always a bit painful when you’ve finished the previous day’s data collection around 8:30pm. However, I do prefer morning tides than the late day ones, as the light is much better. There is also a rewarding feeling when you have completed your data collection by 10am to be honest, and you still have a full day ahead of you.

The morning of June 20th was promising, with the perfect light (slight overcast rather than full sunshine) and a light breeze too, which keeps the midges away. I arrived at the site before 7am, and spotted a few seals on the first observation point. One of them was Or085, a female that we have known since the start of this project in 2016, and that we also tagged in 2017 with a telemetry tag. She looked very big and thought to myself it couldn’t be long until she pupped now.

Or085 (front)

Once I had taken photographs of these nearby seals I started taking pictures of those further away. As I was scanning the shore with the scope and camera, I catched a seal just giving birth, but of course, I was pretty far away… This pretty much summarizes what has happened over the last 5 years. I see a seal … and then I see a seal with a pup! In this case it was Or045. The pictures below are less than 30 minutes apart…

A pregnant Or045 resting at the haulout site…

… and less than 30 minutes later, with her brand new pup!

Later in the morning I moved to a second observation spot to photograph these more distant seals. As I was finishing off I saw that the first female, Or085, was hauling out straight ahead of me in a nice bit of seaweed that is accessible once the tide has come up quite a bit, and that, as far as I can tell from my observations, is a favorite to the seals on the right tides. I decided to stay around, as I could see Or085 behaving a bit different than usual: changing position quite often, as well as making some suspicious movements that looked a lot like contractions to me. So, after 5 summers of coming to Orkney to monitor the harbour seals during the pupping season, I finally managed to see a full birth, which was very exciting and incredibly interesting. The video below is a summary of that process. Be aware that it does show a seal giving birth. Once the pup was born, there was a lot of nose-to-nose interaction between the mum and the new pup, which is very important to set the bond for a mum-pup pair. The pup then suckled for a bit and, with the tide coming up, both mum and pup ended up in the water (although the pup needed some encouragement).

 

Or085 and her new pup

Suckling time for Or085’s new pup

Since June 20th, I have been going back to the monitored site, and have seen Or085 and pup together, which is great news. Because the pup already has its adult coat with pelage markings, I should be able to identify it at least within this season, and check for how long it stays associated to mum.

Or085 and pup seen on June 21st

Written by Monica

2019 pupping season

It doesn’t feel that long ago that I was saying my goodbyes to Orkney at the end of the pupping season last summer. Well, we are back now and actually already two weeks into our 4th field season of this project (well, 5th year of fieldwork, but 4th photo-identification data collection year!). There is always a sense of excitement the first day going back to the field sites after all these months. Since we left at the end of last July, these harbour seals have undergone an annual moult (around August), a mating season, and a whole autumn and winter of foraging in the North Sea waters, and for the females, also preparing to pup again this summer. It was thus nice to recognize some familiar faces, like Or008 and Or023, two females that are frequently seen in a small haulout site in Widewall Bay, in South Ronaldsay. I normally do not tend to photograph seals in the water, as it is more difficult to get good head profile photos, but these two were posing just perfectly for me!

Harbour seals tend to come back to the same haulout sites every summer for the pupping season. That alllows us to follow the same individuals over the years, recognizing them based on their unique pelage markings, and noting relevant information to answer our research questions. It is of course possible that we might see some seals only once in the entire summer, while others are seen on a daily basis. Not all seals follow the same pattern, but, in general, they tend to be at a haulout site at some point or another during the season. As long as we go out regularly to check on them, we should be able to photograph them and thus have a record of their presence! Sometimes, however, we might not see one or more seals at all. That could be because they are elsewhere, or we just do not manage to see them when they are around, or they have have died; the numbers of harbour seals in Orkney have been declining continuously at a rate of 10% each year since 2001. The last count in Orkney and the North coast was in August 2016, when 1,349 harbour seals were counted compared with 1,938 in 2013. Overall, the composite counts for the North Coast & Orkney Seal Management Unit (SMU) have declined from approximately 8800 in the mid-1990s to 1350 by 2016, representing an 85% decrease in what was the largest single SMU population in the UK. The counts for the Sanday Special Area of Conservation show a similar trend, with a step change between 2001 and 2006 and a continuing decline at 17.8% p.a. (95% CIs: 13.3, 22.0) since 2006. There is more detailed information on the counts and population trends of grey and harbour seal populations in the annual reports to the Special Committee On Seals (SCOS), which can be found in the SMRU website (see this link). By collecting this annual data on presence/absence of known seals and their associated pupping history we can learn about their survival and birth rates, and how these help explain the observed declines, increases or stable trends in different areas in Scotland.

August counts of harbour seals in Scotland, taken from the 2018 SCOS report. See http://www.smru.st-andrews.ac.uk/files/2019/05/SCOS-2018.pdf

So far the weather in Orkney has been… well, Orkney weather. I’ve had dense fog, beautiful sunshine, incredibly strong wind, thuder and lightning, heavy rain and a gazilion midges. Despite that I’ve managed to get out more or less every day to check on the seals. The numbers have been increasing at the monitored sites, with more heavily pregnant females. Then on June 12th I saw the first pup! It was in Widewall Bay, where Or075 decided to haulout with her new pup as I was getting out of the car. Good timing!

Or075 with her pup on June 12th 2019 in Widewall Bay, South Ronaldsay

Since then there are at least another two pups in that same haulout site, from females Or007 and Or135. At another monitored site in Burray, as of yesterday 17th of June I have identified 4 pups, belonging to females Or024, Or025, Or065, and Or146. I am expecting to see a few more in the next week or so, at least by the looks of some of the females such as Or142… ready to pup!

Or007 with her 2019 pup. Check how dark is this pup compared to mum! (she is particularly pale too…)

Or024 and her pup

Or142 resting under the rain… look at that belly!

Written by Monica

 

Andy

This is a post I never thought I would have to write. Earlier this year we received the devastating news that Andy Law, one of our team members, had unexpectedly passed away. This came to an absolute shock to all of us that knew him. Andy was a much liked and respected member of the SMRU team; his enthusiasm for all nature related subject was contagious and his knowledge on the local (and not so local) wildlife was absolutely admirable.

Andy helping with SMRU fieldwork in Kylerhea

Andy joined the Harbour Seal Decline project from the start, by leading the exploratory trips around Isle of Skye and part of the Argyll coast back in the summer of 2015, to choose potential study sites to get data on harbour seal population demographics. He then went onto taking responsability for collecting the photo-identification data of harbour seals occurring at the study site in Loch Dunvegan (Isle of Skye), and then patiently and methodically processing the thousands of photographs collected. But Andy was known to the SMRU team way before that, as he had been collaborating with various projects occurring in Kylerhea waters in the past, right on his door step.

A mum-pup harbour seal pair from Loch Dunvegan. Photograph by Andy Law

Andy’s ability to recognize the different seals frequently seen in Loch Dunvegan was something else. He literally knew by eye a very large proportion of the around 500 catalogued seals in that area… Not only that, but he also managed to nickname most of them based on what the pelage pattern looked like! Andy was a very talented wildlife and landscape photographer, which was reflected in the photographs taken for the project. Despite being busy taking pictures as the boat would move fairly quickly past the hauled out seals, Andy would still find the time to chat to those lucky ones happening to be in the same wee boat with him, answering all the seal or other wildlife questions they had.

Harbour seal pup from Loch Dunvegan. Photograph by Andy Law

Curious harbour seal in the water. Photograph by Andy Law

Andy is and will be truly missed by all of us that were lucky enough to cross paths with him. Our thoughts are with Andy’s wife Debbie and his kids, Hamish, Isabelle and Madeleine.

Post written by Monica.

 

 

Back to the office

Last month we said our good-byes to the seals as the field season concluded at our study sites in Orkney, Kintyre and Isle of Skye. All teams have taken a well deserved break from the field, and the office work welcomed us back with a big smile. Until the next fieldwork season starts in June of 2019, the time will be mostly spent processing all the pictures collected, meaning our computer screens will most likely show seal faces for the next few months:

Part of the seal catalogue for Orkney, showing the right-hand side of each identified seal

Once the photographs for the season have been processed, we can have a look at what the data shows. We can figure out how many seals were seen, and in the case of adult females, we will have information on whether they had a pup or they did not. Of course it might be that a female had a pup but we just did not see it, let’s say if that female decided to pup nearby instead of the monitored site. By constructing these sighting histories in consecutive summers, we can learn about the mortality and birth rates that characterize each study site, and find out whether there are any differences between areas where the number of seals have been declining (such as in Orkney) or where the number of seals has been stable or even increasing (such as in areas of the West coast).

Sighting histories of some of the females from Orkney in the summer of 2016, between mid May and the end of July. The different colors represent information associated with each sighting. For example a green dot means we photographed the female on its own, a yellow dot it means we could see it was pregnant, and the blue and red dots mean the female had a pup with her.

The pelage of harbour seals comes in all kinds of colors, as the proportion of dark and light colors changes across seals. Some seals are very pale, especially in the head area, while others are very dark. Some of the paler seals are especially difficult to identify given the lack of pelage pattern. It gets even more difficult as the summer advances and the time of the moult gets closer.

Or043 is one of the pale females regularly seen in the Orkney monitored sites

Or094 is also a regularly seen female in Orkney but she has a much darker pelage pattern!

Seals will start the moult at different times, driven by the sex and reproductive status, although other factors will have an influence on the timing of the moult, for example body condition, temperature and hormones. Harbour seal pups moult first in utero, before the birth. After that, yearlings, which are the animals that were born the previous summer, will be the next ones to moult, followed by older seals including juveniles, adult females, and finally adult males. This summer, some of seals in Orkney made a good progress of the moult by the end of July, and a few were showing an almost complete new pelage by the end. Who knows, maybe the hot weather allowed them to moult a bit quicker than other summers. Whichever the reason, one cannot deny they look beautiful once the new pelage shows up, and the contrast with the brown looking pelage of just a few weeks before is noticeable.

This female, seen in Widewall Bay, had only a few remaining patches of the old coat around the flippers and nose by the end of July

Or007 showing clear signs of moult, especially around the head on 8th July this year

Or007 showing a shiny new coat on the 25th July this year

Written by Mònica

Another field season completed

Last weekend marked the end of another field season for the project. In Orkney, the vibe at the haulout sites changed significantly during the last week. Most of the pups were observed on their own, and thus likely to be fully weaned, and only a few mum-pup pairs were seen interacting. One of the few left was Or026, which was one of the last ones to pup this year around the 28th or 29th of June, as we explained in this other post.

Or026 in the water with her pup in Orkney

The processing of the photographs from this year is still to be completed, with which we will attempt to identify every seal that has been photographed. Then we can figure out which females pupped this year, information that will be used to estimate birth rates in Orkney as well as at the other study sites. Going out to get the pictures keeps us busy enough, but there is still some basic data processing we have to do everyday after coming back from the field. The photographs have to be renamed with information on where the pictures were taken (because we have several sites that we monitor) and the trip number. Then we have to add the metadata associated to each photograph to a table, so that each row shows all the available information to each photograph. If the photograph shows more than one seal we need to state which seal are we talking about. We can then add information, when available, on whether a female was seen with a pup or alone, on whether suckling was observed, or whether we can tell if a seal is a male or a female from photographs of the genital area.

When a photograph shows more than one seal, we indicate which seal we are referring to by counting the number of seal heads in the photograph and adding the head number for the seal of interest counting from left to right in the frame.

The pups that are weaned or almost weaned look quite massive compared to when they were born, and some of them are so similar in size to the seals born last summer that one needs to triple-check to make sure it is a pup and not a yearling.

Or057 with a rather looking big pup!

Even though the identification of the females that have pupped this summer is still to be completed, we have recognized most of the females. Some of them have pupped for a third consecutive year, including Or094 in Burray, nicked-named “coliflower”, who had her pup on June 19th , and Or044, nicked-named “butterfly”, which is regularly seen in Widewall Bay.

Or094 in the catalogue with her pup in 2016, 2017 and 2018

Or044, “Butterfly”, is regularly seen in Widewall Bay, where she has been seen with a pup for the last three summers

While some pups have been seen suckling from their mums right up until almost the end of July, others that were born earlier in the season were already weaned by then. Some pups have to be a bit more pushy to get the female to lay on its side so that they can suckle. They do so my pushing their nose against the side of mum, until she turns around to get her belly exposed, as does mum Or045 in this video:

The pups that either have already been weaned or might just be spending more time on their own at the haulout sites might still try for a cheeky extra meal if that’s on the offer. In the video below, you can see female Or057 at the haulout sites together with her pup and some other pups. One of them, is trying to slowly approach the female from the the water, but it doesn’t seem that this tactic will work with Or057…

During the last few days of monitoring in Orkney we also noticed an increase in the number of seals starting their annual moult or well into it. More on this in the next post!

Weaned pup checking out a rock to haul out

Written by Mònica

Pup, pup and away!

Kintyre has seen a fair few new arrivals since we last wrote! Firstly, there have been (at least!) ten new pups, with mum and pup pairs observed at almost all of field sites here in Kintyre. And secondly, the arrival of myself, Emily, as another short term field assistant. I’ve been working with the permanent field assistant here, Izzy, for the previous few weeks to gain experience in the collection of seal photo-ID data and to become familiar with the field sites. I work on maintaining the Kintyre photo-ID database back at SMRU, so it has been a great eye-opener to get out of the office and see the sites, the seals, and to see ‘behind the scenes’ how the data is collected. On my return to SMRU I will now be processing the 2018 photographs, updating the catalogue and adding in any new (very cute!) additions from 2018.

A young pup photographed at Seal Rock (photo: Emily)

During the previous two weeks I’ve seen pups at 4 of the 5 field sites, with Yellow Rock the only site where pups have not been observed. This is traditionally a male dominated haul out with few females being observed at this site. Conversely, we have seen the highest number of mum pup pairs at the nearby Muller Island site, observing up to four pairs hauled out in close proximity to each other, almost like a nursery! It’s interesting watching the pup behaviour, resting, suckling, and swimming and attempting to keep up with mum.

Now that some of the pups are two to three weeks old it’s noticeable how their confidence is growing and they’re entering the water alone more, with mum leaving them alone for longer periods of time. It is not long before they will be weaned and separate from mum completely!

A mum and pup pair photographed at Southend. Right after this the pup went for a lone swim while Mum watched from on land! (photo: Emily)

Written by Emily