• David Darrell-Lambert

Research

So, a few years ago I was drinking with a group of birders, we used to always meet up on Christmas Eve in the Westend of London for drink and talk mostly birds all night. Now we are all middle aged and spread across the world, so these gatherings rarely happen. So Sam was explaining to me that someone had carried out some breeding bird surveys in the rainforest where he lives in Costa Rica. They had stated there were few birds present of any consequence. It turned out they visited the site in the middle of the day and unsurprisingly didn’t find many birds. Sam went there at the correct time (pre- dawn) and picked up loads of birds. So now this is a familiar story to me, people surveying at non-peak times of the day. Having birded a patch for many a year I know that birds sing early in the morning. During my early years of carrying out breeding bird surveys I kept moving forward my start time from sunrise to 1 to 1.5 hours before sunrise. After a few times of arriving on site to find the birds already singing, you think well I should be here earlier to catch the start. That way you catch all the early singing birds plus the activity is more significant. In the old days, I would be asked to carry out just one or two breeding surveys on a site. Now the minimum I do is four. So I spread these over the breeding season to give me a good idea of what is present and adjust it for any specific species I may find or think is present.


So what research am I carrying out now, well, I want to know when is the best time to start surveying for breeding birds? Which months are peak for which species and what are the relevant times of the day? Often I am told you need to start no later than one hour after sunrise and I am told that guidelines state this. To me, you’ll miss out on loads of breeding birds such as Song Thrushes which are one of the earliest singing species during the dawn chorus. Now, how do I prove my theory, that you need to be out early?


So my methodology is simple:


  • start an hour before dawn

  • walk 500m in a straight line counting all the singing birds present

  • repeat every half an hour along the same route for six hours, only walking in one direction

  • analyse the data to see peak times for singing during the year per month?

  • analyse the data on a half hourly basis

  • analyse the data per family per half hour per month

  • analyse the data per species per half hour per month

  • all surveys to be carried out in ideal weather conditions, sunny and windless days. No surveys to be completed on days of heavy rain and strong winds - this reduces the territorial behaviour

  • survey once a month a for year for a complete picture


Originally I was going to do this every hour but I soon realised this should be every half an hour. I would need to start before anything starts singing and finish when it all slows down. This would show the peak periods for all birds plus the species that are present.




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