By Marcus Ward, 14 February 2017
In this first ‘pilot’ year, ringing rides were established in the gorse and scrub at Iley Point, Keyhaven Marsh, with a view to better understanding the range and number of migrant passerine species using the area through the post-breeding and autumn migration period. In addition, ringing will enable us to get a better understanding of key resident species in the vicinity, such as Dartford Warbler, Cetti’s Warbler and Bullfinch.
Ringing was conducted on a weekly basis, when weather allowed, between 1st September and 31st October. Over the course of nine sessions a total of 545 birds of 35 species was ringed (Table 1).
A good variety and breadth of migrant passerine species were recorded; of particular note were 17 Grasshopper Warblers caught and ringed in the first week of September. In an average year just one or two of this species are recorded within the SSSI. As the peak of Grasshopper Warbler passage is in mid-August, the overall total of individuals passing through the site could be regionally significant. Other significant totals included 109 Chiffchaff, 93 Blackcap and 45 Common Whitethroat, highlighting the importance of the site for migrant warblers, especially considering that ringing started after the peak passage period.
A variety of resident species were also caught, including some noteworthy species. In particular Dartford Warbler: five individuals were caught including two adult males, two adult females and one immature, suggesting a minimum of two pairs may have bred nearby with some success. Traditionally it was thought this location held just one pair of Dartford Warbler. Subsequently an un-ringed adult male was also observed in the vicinity.
Five Cetti’s Warbler were caught and ringed, including two immatures, suggesting a minimum of two breeding pairs in the vicinity of Iley Point.
At the time of writing we have had three significant recoveries associated with the site as follows:
Chiffchaff (immature, ring no. JTX951)
Caught and ringed at Iley Point, Keyhaven Marsh at 07.00am 2nd October 2016
Re-trapped at Squires Down, nr Sherbourne, Dorest 3rd October 07.30am 3rd October 2016
Travelled 63km WSW in 23.5 hours
Reed Bunting (immature male, ring no. Z837732)
Caught and ringed at Abbotsbury Swannery, Dorset on 2nd October 2016
Re-trapped at Iley Point, Keyhaven Marsh at 10.45am on 29th October 2016
Travelled 74km east in 27 days
Reed Bunting (immature male, ring no. S526424)
Caught and ringed at Iley Point, Keyhaven Marsh at 08.30am on 7th September
Re-trapped at Batchley Farm, Everton (by Avon Water) on 31st December
Travelled 4km north in 115 days.
In addition a number of re-traps involving both resident and migrants species were caught over successive weeks, illustrating that migrants are not only passing through but using the site to feed up prior to departure further south.
To get a clear and comparable set of data, future ringing will need to encompass the entire post-breeding and autumn passage season. This typically runs from 15th July through to 31st October, although passage does continue into the early winter period. We will also conduct a few sample sessions outside of this period, perhaps monthly throughout the year to get a snapshot picture of the range of species using the site; this will create a clearer context for the targeted surveying of migrant species in late summer and autumn.
Again, in order to build a better understanding of the importance of the site, it is intended that ringing will continue for a minimum of 5-10 years in order to assess consistency and to iron out any anomalies encountered due to weather and changes in status of certain species.
Thanks to Pete Durnell and Simon Curson for arranging access and providing the relevant permissions. Also thanks are due to my ringing trainer, Graham Giddens, for helping out with many sessions, greatly increasing the numbers of birds processed.
Table 1. 2016 ringing totals from Iley Point, Keyhaven Marsh