My observations continued at the Dipper nest today. Building continued unabated and with  zeal by both birds. I watched from just after 9 until 12.40 and for that entire period they mostly took it in turns with the female perhaps doing the lions share. Yesterday, moss was almost entirely used but today a variety of materials included leaves and grasses and even a dead fern frond. Without exception every beak full was dunked and thoroughly soaked before being take to the nest, obviously an in-bred instinctive behaviour.

One of the pair flopping in to the water beneath the nest after being relieved by it's mate.

The male was more likely to take a feeding break, which he did  on several occasions but the female only once.  Food seemed incredibly easy to come by and I watched the male successfully find prey on every underwater foray which took just a few minutes. The sibilant noise that accompanied every arrival at the nest, particularly by the male, was hardly made today particularly as the session went on. The method of building involved much poking and pecking and the new material was woven and pushed in to the existing fabric of the nest.  Only one bird at a time would work on the nest with each bird usually remaining at work until it was relieved by it's mate.  When exiting the nest both birds  flopped in to the water in the same manner and swam with the current to a favourite rock in the stream.  They would then decide in which direction to fly to gather more material.

Flying to the mid-stream rock after dunking nesting material.

On returning to the nest they would arrive in flight to the same rock after first wetting the beak full of material before flying up to the nest to relieve their mate.  On some occasions the delivering bird would immediately leave with a full beak knowing that there was not room for both birds to work at the same time. This seemed to be cognitive behaviour.   All nest building came to a sudden end at around 12.40, pretty much exactly the same time as yesterday and like yesterday, the male perched on a boulder and sang to proclaim his territory. By 1.00 both birds had departed the nest area. 

The male perched opposite the nest at the end of the nest building session.