Strumble Head – Tern bonanza, 18 August 2012

So what are the ideal weather conditions for Sea-watching at Strumble? Well – ideal for what? Many people quote the wisdom that you need SW winds to set the birds up and then a NW blow to push them back past the headland – the “classic conditions”. While it cannot be denied that these conditions have produced great days in the past they have also produced very quiet days – the birds have to be out there in the first place!

There are many many variables to a “good day” at Strumble and we are still learning even after the extensive coverage the headland has had since the 1980s courtesy of the great pioneers of this site – Graham Rees et al. Only one thing is certain when it comes to sea-watching – “Expect the unexpected!” You have to be there to see the birds – they will not wait around to be twitched! It is also worth noting that some of the best birds past this headland have come through on quiet days. The more you watch from here the more you learn and while you can never predict a good day you can identify certain conditions that “might” produce the goods. One such event took place on Saturday 18th August 2012. I was set to be down at my house for the weekend and was hoping to get some big hours in sea-watching.

The Friday evening weather forecasts were predicting Southerly winds of light to moderate strength with drizzle and reduced visibility. Given that forecast how many birders in the county would think – I know a day at Strumble would be good? When I saw that forecast my instant reaction was that the weather sounded good for tern passage. Over the years I have noticed that these conditions in mid to late August are reasonably good for terns. They like to fly into a head-wind and if the visibility is poor they fly straight in to the headland and then pass by at close range. These days are exciting as the terns are very hard to spot when they are coming in head-on and so they seem to just appear from nowhere as they hit the coastline and funnel through to the west.

One such day will live long in the memory from a few years ago – a day when hundreds of Black Terns passed the headland witnessed by Graham Rees and myself. The passage took all day and smashed records but the strangest thing was that the terns, coming through in groups, all reached a certain point (bearing of 11:30 from the lookout and out over the tide-race) at which point they circled round and then gained height and disappeared up into the clouds. Why? What caused them to do this? How did they keep doing this all day long – even when there was sizable gaps between groups coming through? – i.e. one group couldn’t have witnessed the previous group doing this disappearing act but time and time again they just kept doing it! I guess we will never know!

Anyway back to Saturday 18th. I arrived at the lookout and was set up for 6am. The wind was blowing about a Force 4 from a SSW direction and as predicted there was drizzle that was reducing visibility. It became immediately obvious that my tern prediction was looking good as some of the early birds were small numbers of terns – mainly Common and Arctic. As normal I tried to i.d. those that I could and found that the ratio was roughly 3:1 Common to Arctic but as the numbers started to build it became a case of logging the “Comics” and trying to keep an eye open for other species. The Comics just kept coming and they started to come in bigger and bigger flocks. I had a number of flocks during the day of at least 100-200 birds at a time. The passage continued for the entire day. I eventually packed in at 18:30 – a 12.5 hour shift! It was hard work, I almost needed my calculator at times. I am an accountant by profession but didn’t think to pack my calculator for a day at Strumble! Later in the afternoon the weather broke and the sun came out giving a glorious evening but the terns kept coming through and only started to quieten down when the light started to fade.

My count of Comics for the day ended with 2,133 birds – a day record for Strumble. To put that into context for the county a look at the 2007 to 2011 bird reports shows the total number of Comics seen in the county in each of those years in all months and at all locations as 424 (2007), 944 (2008), 1,169 (2009), 2,283 (2010) and 2,211 (2011). As you might expect there were a small number of other tern species caught up with this passage. The surprise being a meagre total of only 30 Sandwich Terns. Other counts were 177 Black Terns, 9 Little Terns and 5 Roseates. As with August watches there were many other species such as waders, 12 Skuas, a Sooty and four Balearics. Not a bad day!

Richard Stonier

Records extracted from the Pembrokeshire Bird Reports which may contain more detail than shown here