Evidence found of rarity on the patch

I was up early this morning to take Toby for a pre-dawn walk to Merton and back.  This early walk produced a number of calling Tawny Owls and an overhead passage Wader species giving an occasional "peep" call.
Once back from the walk I prepared for my morning of searching for migrants along the Watton Brook Valley, specifically, the Little Cressingham and Bodney areas of The Brecks.
Setting off prior to 0600 and with a temperature of 16 degrees celsius, I reached my destination and started my walk.  By the afternoon the temperature reached 30 degrees celsius.


Impaled Beetle at Bodney, Norfolk 22/08/15

What happened next was unreal.  I was walking along a wide verge with posts and barbed wire fencing, my thoughts immediately was of a probable Shrike species which occured here a couple of years ago at the end of August 2013.  Then, I located an impaled Beetle species on a barb.  I walked past where I found the unfortunate beetle, and about 20 feet or so further along the fence I saw something different on barb, would you believe it, I located another impaled Beetle on barbed wire, but on this occasion, the insect was I think freshly impaled as it was struggling with leg movements. 
From this point on a search started for the bird responsible for impaling the Beetle, undoubtedly a Red-backed Shrike, although Woodchat Shrike should not be discounted given the patch record from July 1995.
Looking more closely at the Beetle, there was a small indentation on the upper wing casing, this I think could have been where the Shrike had held the Beetle whilst securing its prey onto the barb.
My first search of the area lasted some 4 hours, I checked all fences, ditches, bushy hedgerows, and also staked (no pun intended) out the impaled Beetle for some time in a hope the bird would return to its larder.  Despite this search I did not locate a Shrike, sadly another visit a few hours later, lasting some 2 hours, did not reveal the bird.
To conclude, why has evidence of a Shrike been seen again, and almost to the week when evidence was seen two years ago.  The first thought is a migrant Shrike, however, given ample habitat for this species to breed in, could it be an unpaired bird hoping for a mate to pass his/her way.  Food for thought.