Marcus writes:
This year, as part of our ongoing study of Hawfinch in the New Forest we have deployed 10 combined GPS/Radio tags on Hawfinch in the Bolderwood area specifically to investigate the following:
- Pre-breeding courtship behaviour and movements
- Foraging behaviour of breeding male Hawfinch
- Post breeding behaviour and movements of adult female Hawfinch with young
This has involved an enormous amount of fieldwork in addition to many hours behind the scenes planning and preparing for the fieldwork, which started in January this year so the first tag could be deployed in April. Overall, countless hours were spent sat in hides waiting for the right bird to visit to enable capture. Once tagged, the tracking started, this year a small team of three core trackers put in a total of 600.5 hours tracking between 08 April and 03 July, missing just six days in that period due to bad weather (the equipment doesn’t work well in the wet, whereas the surveyors dry out more easily!).
Hours in the hide haven’t been tallied at the time of writing (probably best we don’t know!), but the team have put in over 86 days of fieldwork including 1000 hours of field-time ringing and tracking Hawfinch.
Tagged adult male Hawfinch 'BJ' at the bait station
As a result, we have a wealth of data to work through before we can publish results, however we can share some headline data as follows:
Pre-breeding courtship behaviour and movements
Two adult male Hawfinch were tagged (08 April and 23 April) and tracked, both ranged widely across the New Forest. One particular individual ranged between Bratley Inclosure, Knightwood Inclosure and Wilverley Inclosure, roosting and displaying courtship behaviour in numerous locations. This has changed how we interpret this early season behaviour, with individuals ranging far more widely than previously thought. This will change how we assess the number of breeding pairs in any given area, helping us to more accurately estimate the size and distribution of the New Forest population.
Foraging behaviour of breeding male Hawfinch
Following on from our tracking work in 2019, five adult male Hawfinch in breeding condition were tagged. We specifically targeted known individuals in peak breeding condition to ensure we were tagging birds that were actively nesting. The main aim was to gather data to support findings from our earlier study looking at foraging behaviour of breeding males. Initial results appear to support our earlier findings - adults forage for the nest in the vicinity of the nest, generally deciduous woodland presumably foraging for invertebrate prey. The males also frequently visit areas of Holly where they appear to feed on the ground foraging for Holly seeds, presumably finding sustenance for themselves highlighting the importance of these Holly holms as a food source for Hawfinch, especially in years when the Beech mast crop is poor.
YouTube clip of tagged male LH at the nest with female Hawfinch: https://www.youtube.com/watch?v=3bR48CWVGU0
In addition, we checked roost site locations for each tagged male and found, as before, that when nesting in the vicinity of a communal roost the males appear to use the communal roost site. However, when the nest is some distance from a roost (>1km) the male opts to roost close-by the nest. Further analysis of our data from 2019 and 2021 is required before we publish further findings.
Post-breeding behaviour and movements of adult female Hawfinch with young
Three adult female Hawfinch were tagged in the post-breeding period to further investigate post-breeding movements and possible communal behaviour. This was by far the most challenging part of the survey; first of all we needed to confirm which of the regular colour-ringed females in the area actually had a brood of young, then we needed to catch the individual which involved countless hours in the hide targetting the right bird at the right time. Once tagged, the challenge of tracking a famously difficult-to-observe species in the field began. This was made more complex as we also needed to interpret what the bird was doing to understand the bird’s behaviour.
Full results will be published in due course, as we still have many thousands of trail camera images to sift through and add to the data before analysis can start, but watch this space for further updates.
Helen tracking at dawn in the central New Forest
A final mention has to be made of the team – Marcus Ward, Andrew Colenutt, Helen Schneider, Georgie Digby, and Jamie Ward, without whom none of this would be possible. Andrew and Helen deserve special mention in particular, between them they did the lion’s share of the tracking and ringing, putting in many hundreds of hours in the field tracking and ringing (in addition to juggling their day jobs). They would frequently be out in the field at 4am and still be out there checking on roosting Hawfinch at 10pm!