Surveying the Birds at Knepp Estate!

Knepp Estate

Intensive farming of Knepp Estate left ecosystem functionality in tatters, however, since rewilding of the 3500 acres began in 2002, this has gradually recovered. But how do we know this? The answer, lots of ecological surveys! Monitoring of the diversity and abundance of a variety of taxa across the estate has revealed the success of Knepp’s approach to rewilding. Establishing the positive impacts and associated timescales of rewilding in the UK was of critical importance and has since catalysed the creation of several more ‘Knepp’s’.

Success Stories

A hands-off approach to nature restoration has proven to be full of surprises! With ‘messy’ scrubland habitats acting as strongholds for populations of iconic species such as the Nightingale and Turtle Dove – birds that are disappearing from the rest of the UK. Turtle Dove populations have plummeted by 98% in less than 50 years earning them the title of the fastest declining bird in the UK. However, there is hope – the number of territories across the Knepp have increased at least 6-fold since rewilding and the Doves can now reliably be seen and heard purring away on site.

Monitoring birds is important, it not only uncovers exciting success stories that have shaped Knepp but is also fundamental for the assessment of environmental recovery. Birds are excellent indicator species due to their high sensitivity to environmental change, meaning habitat degradation as well as restoration directly impact bird populations. Birds indicate habitat quality well as the taxa is dependent on ecosystem functionality, therefore, tracking population recoveries at Knepp can prove the effectiveness of rewilding efforts.

Photos by Georgina Tugwell

So, How Do We Survey Birds?

Birds are well studied, easy to detect by sight or sound and census methods are well developed and relatively inexpensive – the taxon is therefore important to monitor for most terrestrial conservation or restoration projects. There are a number of bird survey methods, those chosen often depend on the research question being asked and on-site conditions. Operation Wallacea have conducted a variety of methods at Knepp since 2021, offering research assistants the opportunity to gain a holistic overview of ornithological survey techniques and skills. These include:

• Mist Netting and Bird Ringing: Licensed British Trust of Ornithology (BTO) bird ringers run bird ringing demonstrations at the estate throughout the expedition season. Bird ringing involves fitting a lightweight, uniquely numbered, metal ring around a bird’s leg, enabling identification of individuals. It is an important survey method that provides insight into bird population trends, migration patterns, wintering areas, longevity and health – answering questions key for bird conservation.
• Breeding Bird Surveys: These ecological assessments are carried out using the BTO Breeding Bird Survey (BBS) methodology which is the main scheme used for monitoring population changes of the UK’s common and widespread breeding birds. Data generated informs on population trends and practicing the survey provides participants with the opportunity to improve bird identification skills by sight and song.
• Point Counts: 10-minute unlimited radius point counts are used to assess the diversity and abundance of birds present within a given area, this strategy informs on the species present in a habitat and can uncover population trends over time. Systematic sampling is advised for point counts where the goal is to estimate population trends for an entire management unit.

Photo by Georgina Tugwell

There are many more aspects of ornithology taught by the course that are not listed here e.g. the different techniques used to capture birds for ringing, GPS tagging methods such as those used for Knepp’s White Storks and the emerging practice of bioacoustics monitoring.

Interested in Learning More?

Joining the Operation Wallacea Knepp Expedition next summer is a great way to learn firsthand how we go about monitoring birds alongside many other things (mammals, herpetofauna, plants, carbon, invertebrates, bats, etc.!). If you think ecology may be of interest to you, the course offers an excellent opportunity to brush up on a number of survey techniques and is guaranteed to leave you inspired to learn more. Having attended the 2021 Knepp expedition and worked every expedition season since then, I highly recommend this course to anyone considering an environmental career.

Title photo by Fran Anderson