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Thursday, 3 October 2019

Goldfinch on seed feeder
Goldfinch on seed feeder (RSPB)

Bromley Garden Bird Feeding Survey

Our Bromley RSPB Local Group has been running the January Garden Bird Feeding Survey since 1979. It was organised by Gordon Dickerson until 1985. Alex James then took it over until 1999, and from 2000 to 2018 it was the turn of Derek McWalter. The number of participants was 18 in the first year, peaking at 73 in 2010.

Participants keep a record of birds seen using their garden on each day in January in which they are able to make observations. The results are then collated, enabling the frequency with which each bird appeared in each garden to be calculated as a daily percentage. So, for example, in 2019 the woodpigeon was the most common bird, appearing on 76.2% of daily lists.

The trends revealed by the survey are fascinating. The woodpigeon is a good example. Back in 1979 it was only the 14th-ranked bird, with a reporting rate of 10.8%. It made the "top 10" in 1989 with 33.6%, and has been in the top 4 every year since 2003. In contrast, the house sparrow has headed in the opposite direction. For 13 of the first 14 years until 1992, it was ranked 1st. Indeed, for the first 5 years of the survey its frequency never fell below a phenomenal 98%. This means that during this period they occurred in every participant's garden virtually every day. Sadly, since then it has slipped down the list until in 2019 it was only 15th, with a reporting rate of just under 25%.

There have been other spectacular movements. In 1979 the goldfinch had a reporting rate of just 2.2%. This put it in 27th place, behind both bullfinch and mistle thrush. In 2005 it broke into the top 20 in 17th place, and for the first time this year it was in the top 10, at no 9 with a reporting rate of 37.5%. Keeping it company on its ascent has been the ring-necked parakeet, which is now ranked 8th with 42.2%.

Some other species have disappeared totally from the list. Tree sparrows were reported in every year except one until 1998, but not since then, whilst marsh tit was reported in 18 of the first 31 years until 2010, but not since. And spare a thought for the gulls. Four species have appeared on the list over time, with the black-headed gull appearing as high as 11th in 1983 with 18.3%. 2019 was the first year in which no gulls of any species were reported.

The survey is running again in 2020, and we need as many members as possible to take part. It's not necessary to keep a record of every day in January, just those on which you are able to make observations. So, if you are away on holiday for part of January, or too tired to observe birds on January 1st as a consequence of over-enthusiastic New Year's Eve celebrations, you can still take part. The recording form is available from the link below.

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