A History of Grasshopper Warblers at Titchfield Haven

Bird ringing studies began at Titchfield Haven in 1973 and in those days the Grasshopper Warbler Locustella naevia was a regular breeder at the site. Between 1973 and 1998 the species was one that was only occasionally caught with 18 birds ringed, the totals are as follows; 1 in 1973, 1 in 1974, 1 in 1979, 1 in 1981, 1 in 1986, 1 in 1990, 8 in 1992 and 4 in 1994. In 1999, the year after I began ringing at the Haven, we decided to try and target Grasshopper Warblers in order to understand more about the migration of the species.

Juvenile Grasshopper Warbler - Titchfield Haven 2014

We sought advice from Trevor Squire, who in those days was the lead ringer at the Icklesham site in East Sussex, as they were catching good numbers annually, and set about our task. We set our nets low to the ground and used tape lures of a singing male Grasshopper Warbler. These were set to come on 1.5 hours before sunrise, as British Trust for Ornithology  guidelines recommend. In our first year we caught 31 birds and were pretty chuffed with our results, but had no idea how the numbers would increase in the future. 

In Birds of Hampshire (Published by the Hampshire Ornithological Society in 1993) Grasshopper Warbler was described as "A scarce summer visitor which has declined considerably since 1970". Cumulative totals of singing males between 1966 and 1990 showed a decline from 139 to 52, so the species was evidently undergoing a dramatic decline in Hampshire. Today the breeding status of Grasshopper Warbler in Hampshire is hanging by a thread with only 12 singing males recorded in 2012 (2013 and 2014 figures are not yet available). 

Despite the decline in breeding numbers, the autumn totals at Titchfield Haven increased from the 31 in 1999 to an annual average of 281 birds. The peak was an exceptional total of 950 birds ringed in 2011, which was also a record year for many species. The total number of birds ringed at the Haven from 1999 to 24th August 2014 stands at 4502, with the grand total standing at 4523.

One of the most interesting facts that we have learnt is the numbers of birds that pass over the Haven during the autumn migration. It is also interesting to note that the first birds are recorded during the second week in July, and can be recorded up to the second week in October, albeit in much smaller numbers. The peak migration period for the species are the last two weeks of August, although there is an initial peak during the last two weeks of July and good numbers are still recorded during the first two weeks in September.

So what else have we learnt? Unfortunately there are not many sites other than the Haven and Icklesham that are ringing Grasshopper Warblers and that is reflected in the number of recoveries and controls that we have had (see below). The hope is that more ringers will try and ring pulli and adults on their breeding grounds so that we could gain a better understanding of where the birds that pass through the Haven come from and are going to. To date we have only had two foreign recoveries, one from France and one from Senegal.

Recoveries and Controls

Y096313             N     3J                      24/07/11          Wheldrake Ings Nature Reserve, Wheldrake, York

                         C      3    Recaptured  14/08/11  IRP   Titchfield Haven National Nature Reserve (SUFF), Hampshire (341

                                                                                km, S, 21 days)

R586576             N      3                       21/08/05  TDC    Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         C      4    Recaptured  25/01/07          Parc National du Djoudj, Fleuve, Senegal, Senegal (4054 km, SSW,

                                                                                1 yr 157days)

R586596           N      3                       23/08/05  BSD   Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         X      0    Dead           30/06/08          Enstone, Oxfordshire (127 km, N, 2 yrs 312days)

T098831            N      3                       17/09/06  BSD   Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         X      0    Long dead   19/02/07          Selbourne, Hampshire (36 km, NE, 155 days)

T617642            N      3                       02/08/08  BSD   Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         C      4    Recaptured  27/06/10          Ailsworth Heath, nr Peterborough (207 km, NNE, 1 yr 329days)

V680118           N      3                       29/08/09  TDC    Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         C      4    Recaptured  15/05/10          Hasfield Ham, Gloucestershire (142 km, NNW, 259 days)

V680191           N      3                       05/09/09  TDC    Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         C      3    Recaptured  11/09/09          Villeton, Lot-et-Garonne, France (727 km, S, 6 days)

Y457414           N      3                       15/09/12  DAB   Titchfield Haven National Nature Reserve (SUFF), Hampshire

                         C      4    Recaptured  12/04/14          Bicester, Oxfordshire (113 km, N, 1 yr 209days)

Titchfield Haven Ringing Update - 23rd August

There is no doubt what the headline species, in terms of numbers has been so far this year, and that is Willow Warbler. We have continued to catch good numbers this week, with another 37 added which brings the total this year to 222. This is already by far the best annual total for the site ever, which surely must indicate a good breeding season for the species.

Juvenile Willow Warbler - one of 19 caught today

Grasshopper Warbler numbers have also started to build this week with 69 new birds added. The total of 31 birds ringed on 23rd included six adults, which were the first of the year. Adult and juvenile Grasshopper Warblers undergo a partial post juvenile or post nuptial moult. In juvenile birds this is not really obvious as all the feathers are fresh, but in adults it results in a mixture of new, fresh feathers and very tatty, worn feathers. There seems to be no strategy as to what feathers are replaced, as throughout the body, head, wing and tail feathers, random feathers can be replaced. The Images below illustrate this.

Adult Grasshopper Warbler crown, note mixture of new (fresh) and old (worn) feathers

Very worn wing feathers of the adult Grasshopper Warbler

Very worn tail feathers of adult Grasshopper Warbler

Of the other key warbler species, Sedge Warbler numbers are on a par with the record numbers of 2011 and 2013, and Reed Warbler numbers are the highest of the last five years. Garden Warbler numbers are also on a par with the record year of 2011 and Blackcap numbers are significantly higher than at this point in any of the last five years. Chiffchaff and Whitethroat are also high and are the second highest totals in the last five years for both species. Cetti's Warbler numbers are also the highest of the last five years, although the numbers have slowed in recent days as the breeding birds have moved away from the ringing area and into the reed beds.

Table summarising key species total up to 23rd August in the last five years

Graph illustrating key species totals over the last five years.

Other notable species ringed this week were the second Lesser Whitethroat and Treecreeper of the year. Both species are only ever trapped in small numbers at The Haven.

Juvenile Lesser Whitethroat - the second of the year

Treecreeper - the second of the year

We had ringed over 220 birds by the end of the session 23rd August. Sedge Warbler (still no Aquatics) was the most numerous species with 69 birds ringed, followed by Reed Warbler (46), Blackcap (35) and Grasshopper Warbler (31).

Bunny Meadows and Curbridge - August 2014

The autumn migration is in full swing now and as I had a day off I decided to spend at least parts of the day birding a few local sites in the hope of finding some migrants. I started at Bunny Meadows around mid morning to coincide with the high tide, as this is usually a good site for waders. As I arrived it was just off high tide and a few waders and gulls were taking advantage of the last remaining areas of intertidal, whereas others were already roosting on the vegetated Islands.

Black-headed Gull - Bunny Meadows

Black-headed Gulls were the most numerous gull species with 104 present, Great Black-backed (3) and Herring (7) were also present but only in small numbers. At this time of year the islands are well vegetated and some waders were making the most of this cover, whilst others roosted on patches of bare mud. Black-tailed Godwits were the most numerous wader species present with at least 148 birds present.

Black-tailed Godwits - Bunny Meadows

Most of the godwits present were adults and moulting into their winter plumage but there were also a few juveniles present too. 

Black-tailed Godwits - Juvenile in middle and adults

As well as the godwits there was also a good selection of other waders present. Curlew (2), Redshank (5), Dunlin (1), Turnstone (1), Ringed Plover (24) and a Whimbrel were the species that I found, but some were difficult to identify in the tall vegetation.

Two Ringed Plover and Dunlin - Bunny Meadows 

Whimbrel - Bunny Meadows

I continued past the islands to the remains of the old causeway, another good bird roosting location. There were good numbers of waders here too, with Redshank (60), Black-tailed Godwit (2), Greenshank (2), Oystercatcher (5), Lapwing (5) and Grey Plover (5) present. Two of the Grey Plovers were adults and three were juveniles, one of the adults had colour rings on its legs, and eventually it put both legs down so I could get the combination. The bird was ringed at Hamble Point by Farlington Ringing Group in January 2009, the subsequent sightings are provided below the image.

Grey Plovers - Both adults, with one bird colour-ringed (see inset) - Bunny Meadows

First Ringed        02-Jan-09 Hamble Point, Southampton Water, Hampshire, S England
Resighted           26-Dec-11 Bunny Meadows, Warsash, River Hamble, Hampshire, S England
Resighted           27-Dec-11 Bunny Meadows, Warsash, River Hamble, Hampshire, S England
Resighted           18-Nov-12 Bunny Meadows, Warsash, River Hamble, Hampshire, S England
Resighted           18-Nov-12 River Hamble, Hampshire, S England
Resighted           16-Sep-13 Hook Links scrape, Hook-with-Warsash, Southampton Water, Hampshire, S England
Resighted           04-Feb-14 Bunny Meadows, Warsash, River Hamble, Hampshire, S England
Resighted           22-Aug-14 Bunny Meadows, Warsash, River Hamble, Hampshire, S England

With the tide now dropping fast my next stop was Curbridge, further up the Hamble Estuary. Curbridge has been good to me in recent weeks and today was no exception. I started at the Horse and Jockey pub entrance and immediately picked up three Common Sandpipers and a couple of Kingfishers. There were small numbers of Curlew (2) and Whimbrel (2) and a handful of Little Egrets (5). There were at least 600 gulls present on the intertidal, which is not unusual, but the fact that at least 287 of them were Mediterranean Gulls was astonishing. Flocks of several hundred post breeding Mediterranean Gulls often form on the arable fields around Titchfield Haven, but I have never seen this many at Curbridge before. One of the adult birds had a green colour ring on its left tarsus, but unfortunately it was too far away to see if any letters were on it.

Mediterranean Gulls, Adults and Juveniles and Black-headed Gulls - Curbridge

Titchfield Haven - Mid August 2014 Update

I am slightly behind with the update for last weekends bird ringing at Titchfield Haven as I have been playing around with my blog template, I hope you like it. Having finished with that for now, and having received an update of the ringing totals, here it is. 

The season has been progressing steadily and the table below details the capture totals up to 17th August for 2011, 2012, 2013 and 2014 and the 23rd August for 2010. Looking at the figures it appears that some species have had a good breeding season once again, the most notable being Willow Warbler. The highest total for Willow Warbler ringed at the Haven in a year is 259 birds from 1981, but that total was skewed as 91 birds were ringed in a small patch of willow near the beach huts along the Meon Shore. The next highest total is 158 birds, from 2010. As of the 17th August, 185 birds have been ringed and interestingly we have captured three different adult birds that were undergoing their post nuptial moult, we have only ever caught one bird before.

Sedge Warbler numbers are also high, although not as high as in 2011 or 2013, and Reed Warblers also appear to have had a good year. Grasshopper Warbler numbers appear to be generally low, but this may yet improve as we caught 17 and 12 respectively, on the 14th and 16th August. Garden Warbler, Chiffchaff, Blackcap and Whitethroat numbers are at best average, but Cetti's Warbler seems to have had another good breeding season.

There were no real surprises to report species wise this week but we did catch our first Lesser Whitethroat of the year, hopefully the first of many.