It’s April and here, in the UK, I am getting going on another season of breeding bird surveys; both professional and voluntary. Currently, I have about fifteen to do ranging from two to five visits each.
The best thing is that I really enjoy this kind of birding and the data collected is of true conservation value.
The voluntary surveys include the continuing breeding bird atlas, organised and run by the British Trust for Ornithology (BTO). This effort, from thousands of volunteers nationwide, provides the baseline information: the abundance and distribution of all breeding birds in Britain and Ireland during the survey period.
On its own, this is immensely valuable. However, it gets even better because this is the third such breeding atlas. Comparison of the results with previous atlases reveals trends in species populations. It can show the true levels of species declines or increases and many associated factors.
The professional surveys look at relatively small areas where some sort of development is proposed. It may be a power station, a road, a pipeline or suchlike. The survey will assess the size of population of each bird species breeding within the area as well as the distribution of each species. The importance of these findings can then be assessed with reasonable accuracy using the atlas data. Decisions then can be made on whether the development proposal is okay, needs modification or is inadvisable.
In South Korea there are numerous development pressures and there is much, very useful information, particularly on wintering and passage wetland species groups such as shorebirds and wildfowl .
I believe that there is good breeding data for some species groups and for some areas but sense that overall, a reliable baseline is lacking. In addition the general feeling seems to be that many species are in decline.
This is where Birds Korea members can do some really valuable work.
Building up a breeding bird database
It’s not essential to have a national atlas to provide a useful baseline. In the UK the Common Birds Census, for example, ran for many years before the first atlas. This data could be extrapolated to show regional levels of species abundance and species population trends.
The database grows from the first record and anyone with some knowledge of birds can contribute useful data. It’s dead easy to walk around an area noting what you see and hear, and where, and record whether or not a species is breeding.
If you do more than one visit to an area over the season you can form a more accurate idea of the bird community. An early season and a late season visit is the preferred method: the early visit catches the early nesters while the late visit picks up the summer migrant species and confirms more breeding.
Transect surveys
A simple and repeatable method of survey is to walk a route through an area for an hour or two and simply record all you see and hear. This is easily repeatable in subsequent months or years and, with sufficient sites being covered around the country, it doesn’t take long for a useful data source to develop.
Mapping surveys
Another useful survey method involves mapping surveys. This is based on Common Birds Census which was developed by the BTO. The basic methods are as follows:
- The survey area receives a number of evenly spaced visits over the breeding season.
- On each visit the location and behaviour of each bird is registered on a map using standardised species codes and symbols.
- These symbols denote activities such as song, alarm, fighting, food-carrying, nest-material carrying and more and, where possible, differentiate between individuals of the same species.
A separate map is used for each visit. Registrations are subsequently transferred to individual species maps where the numbers and distributions of territories can be assessed: the more visits the greater the accuracy.
The advantage of this method is that by repeating the survey over subsequent years the breeding population can be monitored. Over time trends can be detected and, with sufficient such surveys areas nationwide, an increasingly reliable monitoring programme can be developed and maintained.
If you do decide to have a go at breeding bird surveys this spring I think you will enjoy it!
Posted by Admin on behalf of Martin Sutherland, April 2011