The rain is pouring down as I write this, and it's amazing to think that just a few weeks ago we were sitting in the blazing sunshine sorting through mud samples looking for invertebrates. Each year we take a series of core samples from the mud in each lagoon, wash them carefully through a specialist sieve and then identify and count the numbers of invertebrates left behind, to help us work out whether we have enough food for breeding and roosting waders. John and Rosie Solbé, our very capable volunteers who are pictured left, help out with this, and it's always intriguing to find out what's hidden in the mud away from our prying eyes. This year we found a huge 19-fold increase in the number of chironomid (non-biting midge) larvae, perfect food for waders, in the Shallow Lagoon. This shows that keeping water levels high on the lagoon by pumping salt water on in order to control the invasive pond weed Crassula helmsii has had a really positive effect on the number of bugs and beasties in the lagoon. For the first time this year we also did some nektonic sampling, a fancy word for looking at what's living in the water, and to our surprise found that both lagoons are teeming with life - there are lots of 3-spined sticklebacks in the Shallow Lagoon, ideal food for egrets and diving ducks, and the Deep Lagoon was packed with common ditch shrimps. Just shows that you don't know what's out there until you start looking!
Anyone visiting in the last week will have noticed large areas of yellow dead-looking vegetation on the mud in front of the Benarth Hide and round the island shores. In our ongoing battle against Crassula, we've started a monthly herbicide spraying programme to help keep it in check. We try and avoid the use of herbicides on our reserves unless there are no alternatives, but I went to an RSPB conference last week where we talked about the problems lots of sites were having with Crassula, and it looks like that's the best option for us now until someone comes up with a method for biological control (basically finding something that will eat it!).
Migration has been in full swing over the past few weeks, with plenty of waders stopping off on their journeys south - we've had up to 50 dunlin, 27 black-tailed godwit, 3 greenshank, 3 bar-tailed godwit, a knot, whimbrel, a little stint on 23 September and 2 curlew sandpipers. White wagtails have been passing through in good numbers, usually down on the saltmarsh, wigeon, teal and a kingfisher have returned for the winter, we've had the occasional pintail and grey wagtail, and one morning saw an amazing 28 little egrets in front of the Coffee Shop. Maybe they'd heard about all the sticklebacks!