A Moment of Prehistoric Proportions

RSPB Mersehead Blog 29^th June – 05^th July 2024

After the vibrancy of the breeding bird season, the summer months feel naturally calmer on the reserve.  Dawn and dusk choruses alongside the springtime territorial singing of our bird species have now faded into the bucolic bleats of sheep and lows of our grazing cattle.  While these moments may seem and feel quieter, the summertime offers a great opportunity to discover some of the smaller species on the reserve. We will start by looking at a new, yet rather old and very small one indeed.

It's a Bug's Life: A Different Type of Tadpole

While the weather may have been wet and blustery for much of the week, a little ray of hope shone down on Mersehead on Friday when the result of over 20 years of hard work came to fruition as Tadpole shrimp returned to Mersehead for the first time in over 60 years.

Tadpole shrimp (Triops cancriformis) is a tiny and elusive invertebrate with fossils dating back to the Triassic period - that’s older than a Tyrannosaurus Rex!!

Adult Tadpole Shrimp. Photo Credit: Larry Griffin.

Once widespread, Tadpole shrimp were until this Friday, only found in two locations in the UK, Caerlaverock and the New Forest.  They were known to have been historically present at Mersehead, and so when they were rediscovered at Caerlaverock over 20 years ago by Dr. Larry Griffin, work began to translocate (reintroduce) them to Mersehead.  Over the years multiple organisations have been involved in the project and it is thanks to the work of RSPB, Species on the Edge, Buglife and of course Dr Griffin that things have reached this stage.

During my own time at Mersehead, the team has been monitoring possible locations across the reserve to understand if they would be suitable for the Tadpole shrimp.  Much like our Natterjack Toads, they like brackish or ephemeral pools that can dry up completely and then suddenly flood.  In fact, one of the key considerations of this amazing project was to try and understand how the translocation may impact our Natterjack Toads, particularly their tadpoles which are vulnerable to invertebrate predation – don’t worry it’s good news, as by the time the Tadpole shrimp hatch from their eggs the Natterjack tadpoles are in the Toadlet stage (more on that later) and in no danger.

All of the pools we have been monitoring are currently completely dry which provided the perfect opportunity to progress with the project.  For some time, eggs have been harvested from the Caerlaverock population with the idea of moving them to Mersehead.  Finally, after all the hard work, today saw 10 kilograms of over 20,000 eggs spread across our predetermined sites.  What we need now is the soil to dry out further and then some rainfall (shouldn’t be too difficult for the second part…) so that the eggs can hatch and adults can emerge.

Tadpole shrimp eggs placed at one of our locations on Mersehead. Photo Credit: Nick Bone.

Tadpole shrimp eggs being placed on location by Dr. Larry Griffin and Buglife's Conservation Director, Craig Macadam.  Photo Credit: Nick Bone.

A huge congratulations to all involved and a real feather in the cap for Mersehead to now be one of only three locations in the UK to have this special species present.

Nattering on about Toadlets

As I am sure you have read in previous blogs, we are currently monitoring and counting Natterjack toadlets on the reserve.  This week we were joined by our Tuesday volunteers as we went in search of the tiny toadlets.  More good news as we found plenty thanks to the extra pairs of eyes!

Time flies when you are craning your neck so hard to find such tiny toadlets! Photo Credit: Nick Bone.

A sense of how tiny our toadlets are, and why people are bending their backs in the previous photo! Photo Credit: Nick Bone 

They might be tiny but they really do resemble the adults even at this early stage.  Note the distinctive yellow stripe and those warts.  Photo Credit: Nick Bone.

When you are keeping a keen eye out for the littler things you tend to find, well other little things!  I promise I wasn’t too distracted however I did particularly enjoy seeing either a juvenile male or female Common Darter Dragonfly in the soft rush when counting toadlets. How do I know it's not the male? The colour is the give-away, the male is orange/reddish but becomes brown with age.

There is nothing common about this dragonfly! The Common Darter (Simpetrum striolatum). Photo Credit: Nick Bone

Weekly Moths

As we have mentioned in previous blogs Mersehead is proud to take part in the Garden Moth Scheme and this week we had some crackers, my personal favourite was the Poplar Hawk-moth but the Burnished brass was also a beauty.

Poplar Hawk-moth from our moth trap this week. Photo Credit: Nick Bone.

Burnished Brass from our moth trap this week. Photo Credit: Nick Bone.

Nick Bone, Trainee Warden

Upcoming events: For more information on individual events and to book a place, please go to our website: https://events.rspb.org.uk/mersehead

 At Mersehead you will find the RSPB’s only self-catering holiday cottages - Barnacle and Shelduck. Available summer dates are currently going quickly, follow the links to book your next holiday.

*Flooding - Please note that Mersehead nature reserve is prone to flooding during periods of high rainfall and/or strong winds and tidal surges. To avoid disappointment at these times, please contact the reserve in advance of your visit by email in the first instance at mersehead@rspb.org.uk or check the RSPB Dumfries and Galloway Facebook Page for daily updates.