Costa Rica Butterflies November 2024 - Part 1

Where to start with our trip to Costa Rica last November? It wasn't exactly the holiday of a lifetime that we expected, but it was a fantastic experience nonetheless.

We should have realised when the pilot informed us that our flight would be landing a little later than expected because we would have to fly around Tropical Cyclone Sara. I never imagined that the deep depression over the Gulf of Mexico, which slowly moved west and north, would have such an impact on the weather in western Costa Rica. We didn't get much wind at all, but what we did get was rain! Lots of rain! The first few mornings were cloudy with occasional sunny spells turning to rain by about 11am which would continue for much of the day.

We visited Nicaragua on the fourth day of our holiday where the weather was reasonably dry, but on our drive back our guide informed us that it had rained all day in Costa Rica and that the road back to our hotel was flooded. Luckily the water had reduced enough by the time we passed to allow us to get back safely.

For the next three days the rain just didn't stop. We were told that in that time as much rain had fallen as would normally fall in a whole year in that area. There were mud slides and flooding causing great damage to the roads and airport. The weather slowly improved after that, but there wasn't a day without some rain and it was only on the last day of our two-week holiday that we had a sunny morning with cloudless skies!

I say two-week holiday, but the rain caused damage to the runway at the airport, so many flights in and out were cancelled. Luckily the airport opened the day after our flight was due, so we were only delayed by one day.

We were staying right up in the north west of Costa Rica, very close to the Nicaraguan border. This is a coastal area of "dry forest" - mostly deciduous trees. We were there right at the end of the rainy season and should have expected a heavy shower maybe every second afternoon.

Unfortunately, the weather also meant that the national parks were all closed, so we didn't have an opportunity to venture into the cloud forest or any other parts of Costa Rica. Therefore, butterfly viewings were restricted to what I saw in the mornings at the resort, or along a track opposite the entrance to the hotel.

However, the few sunny spells we had really showed the potential for butterflies. I was amazed that after a day or two of non-stop rain, as soon as the sun came out butterflies would take to the air. They must be expert at finding good sheltered spots. I also noticed that about ten minutes before the rain started all the butterflies disappeared, so they seemed to know when the rain was about to come.

In the mornings, when it wasn't raining there were almost always butterflies in view. The hotel had enormous grounds with meandering swimming pools surrounded by tropical gardens. It was mostly various shades of yellow, or white butterflies that were flying around there interspersed with all sorts of other shapes, colours and sizes. By the afternoon there were fewer butterflies around.

There was also an amazing variety of other wildlife that frequented the hotel grounds and surrounding forest. The air was always full of bird song and other strange noises, including the roar of Howler Monkeys. White-faced Capuchin Monkeys paid regular visits to the hotel and its grounds and I saw Spider Monkeys just outside the hotel. There were several other mammals and also various Iguanas, Lizards and Skinks all around.

Despite the weather and limited search area, I still managed to identify 68 different species of butterflies and I saw many more fly past that were impossible to identify. Given that over 1,800 species of butterflies have been recorded in Costa Rica along with over 12,000 moths, it is understandable that butterflies need to be clearly photographed in order to identify them. Further complication is added by the enormous number of mimic species of both butterflies and moths and that a number of species have wet and dry season forms and males and females that look completely different!

On that final sunny morning I couldn't believe the number of butterflies flying everywhere and I saw several species that I hadn't seen in the previous two weeks. And on the drive to the airport there were all sorts of amazing butterflies flying along the edges of the roads. I can hardly imagine how many more species I would have been able to see had the weather been better and we could have travelled to different areas of the country.

Over the next few posts I will show the butterflies I managed to photograph.

East Lothian Butterflies 2024 - Part 2

Continued from my previous post.

The number of Small Skippers recorded took a dip after they have been increasing since they were first recorded in East Lothian in 2011.

Large Skippers are now found all across East Lothian, but we only receive a few records. I think it is quite a difficult butterfly to spot and identify as it zips about between flowers.

Ringlet numbers were a little lower than average, but nothing significant. 

However, Meadow Brown numbers were down to about 75% of the average.

Holly Blue numbers crashed. After the odd sighting for many years their numbers have increased since 2019. They started off very well in the spring of 2024, but the summer generation was very much lower than expected. Across England the annual population fluctuates in response to a parasitic wasp. This wasp was discovered in 2024 by a local enthusiast who had reared some Holly Blues, only for some to fail with wasps appearing from the chrysalises.

There are a number of small, isolated colonies of Northern Brown Argus across East Lothian. They are found north of Traprain, east of Dunbar and in the Lammermuirs. Some of the known colonies may have died out and there are likely more undiscovered locations. Because of their remote locations we struggle to monitor how they are doing. In 20224 the Countryside Rangers received funding to plant Rockrose at a coastal site and they worked with Bear Scotland to plant up a south-facing road verge. Once these are established they will hopefully these will provide stepping stones between the existing colonies. 

Grayling butterflies continue to be found at three semi-urban sites. Sadly two of these locations are being developed, so I suspect we may lose those colonies. The exciting new was that there was a Grayling photographed on North Berwick Law last summer and they were also seen in the Lammermuirs.

The Small Pearl-bordered Fritillary is a rare butterfly in East Lothian, but they are found in a couple of locations in the Lammermuir Hills. They were seen in one of the Lammermuir valleys last summer.

And finally, hairstreaks! We have long been aware of a few small colonies of Green Hairstreaks around East Lothian. They are mostly in quite remote locations in the Lammermuirs, so I don't often receive records of them. There was a colony in Saltoun Big Wood, but there have been no Green Hairstreaks recorded there in the last few years, since there was a fire in the small area of woodland where they were found.

Having found adult Purple Hairstreaks in 2022 at Woodhall and Dunglass, two enthusiasts returned to East Lothian to search for eggs last winter. They did a very thorough job collecting carrier bags full of terminal buds from fallen Oak twigs and branches and searching them with a magnifying glass to look for eggs. Amazingly they were successful in finding eggs in six woodland across East Lothian. The adult butterfly rarely leave the top of mature Oak trees, where they can be seen flying in the late afternoon and early evening. Despite a lot of effort searching these woods in the past Purple Hairstreaks haven't previously been recorded in these locations.

Probably the most exciting news of 2024 was the sighting of a White-letter Hairstreak in a garden in Haddington. This is the first sighting of this species in East Lothian. They have made their way out of Northumberland and into the Scottish Borders over the last few years, mostly along the Tweed Valley. So, this is a big jump for the species. However, one was also recorded in Edinburgh and another in Dundee. It is fascinating to consider how these butterflies have spread so far, or if they have been there for a while. It will be interesting to see how they do over the next few years.

It certainly wasn't a great year for butterflies, but I think East Lothian probably did better than the UK as a whole, with one or two species actually appearing in good numbers. Some of the species such as Meadow Brown, Comma and Red Admiral did amazingly well in 2023, so the lower numbers in 2024 are almost to be expected.

Certainly I noticed that numbers where I live in the Borders were pretty similar to East Lothian. Given the wet summer that we had it isn't really surprising that numbers were a bit down. The next few years will give a better idea of how things are going. Let's hope for some decent weather!!

As always, thank you very much to everyone who took part in a transect or who sent in records. I am always delighted to receive them.