Iridescent 

It's the time of year when birds start to switch from wintering to breeding 'mode'. Some changes start to take effect before migration, some are obvious to us and some are not. Teal have been over wintering at Marshside for some months and completed their eclipse phase some time ago. Despite sporting summer plumage for some months, they seem to have developed a deeper iridescent quality in the recent warmer weather. Its amazing how this blue/green teal colour can appear distinctly one or the other as they move around the light. Their behaviour has started to change too, with pairs more likely to break from the flock and dabble in courtship behaviour before remembering they have a journey to make first to their breeding grounds on the northern moors and mires.  

Shelduck and shoveler are often overlooked as 'iridescent' species. Although they have been in breeding plumage for some time, they appear to be stepping up their glossy game of late. 

  

Tufted ducks appear jet black in some lights, but at the right angle colourful purples and a shimmering of green can be picked up. 

These subtle colourings and coatings are predominantly found on the 'showy' male birds. Creating the most colourful/glossiest display is a sign of fitness, as it takes a both energy and micro nutrients to develop and maintain. This indicates both good genes and good foraging behaviour to any would be suiter. This effect must be more evident from a birds perspective, as they can perceive light at higher wave lengths to us.  

Another sign of birds getting into breeding condition can be heard. A particularly striking sound is that of little grebes, their explosive chuckles can now be heard ringing out across the marsh.

  

Some familiar colours are coming back to the black-tailed godwits on the reserve as their infamous rusty plumage starts to develop. Some of these birds will be getting ready to head to Iceland and breed, while others sit the season out remaining at Marshside.

  

Arrivals and Departures

Avocet have started 'prospecting' at Marshside and Hesketh Out Marsh. The first 15 arrived a few weeks later than last year, but with the sporadic winter sightings including a very unseasonal visit to Hesketh we wonder if a few wintered out on the estuary. Almost fifty have now been recorded, mostly standing together on Rimmers and Sutton marshes, but occasionally starting to act territorial around the pools.  

The wintering pink-footed goose population has started to hit a transition stage. As when they first arrive the population increases and decreases suddenly. The decreases represent the birds leaving for Iceland (mainly) and the increases are from populations further east enjoying a 'pitstop'. This time of year they often spend more time towards the top of the saltmarsh along Marine Drive, and the current road closure makes for excellent views.  

Signs of Spring

As well as the changes in the birds of Marshside, non avian signs of spring can be seen. The first frogs have been seen emerging from their hiding spots, much to the delight of the returning little egrets. The hares have also been acting in true 'mad' fashion and small patches of snowdrops and daffodils can be found along the flood banks. It remains to be seen whether the temperatures will hold, or whether winter has one last reach.    

  All images by Wes Davies - Spring 2021

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