I have a daily feeding frenzy in the garden after I put the seeds out. The hawthorn hedge at the back of my garden is host to dozens of house sparrows. The problem is counting them as they flock into the garden for a short while, mill about a lot before a jackdaw or rook will fly by and the whole lot will scoot back into the hedge for thirty seconds before braving the garden again. The only way to count them is to count groups of ten. With practice this can be quite accurate and doing this several times gives a fairly consistant number. I had 75 house sparrows this year, something I am pleased with as when I moved here 7 years ago there was a population of around 10. This begs the question whether my year round feeding has helped boost the success of the house sparrow or whether the sparrow population from miles around have moved into my garden.
Last year I had a huge murmeration of starlings that visited on counting day, and I had to use the similar process for counting these. Down from 40+ to the regular 8 this year.
I wonder whether localised huge populations are discounted as statistical anomolies or whether they are included in the figures.