It’s been another busy few weeks of sightings on the reserve with more summer migrants arriving, an interesting variety of passage birds moving through, and increasingly more insects being seen as we move further into spring.
The appearance of a red-rumped swallow on 11/4 was undoubtedly the overall highlight (photo by Sophie Dorman), another species normally found no closer than southern Europe, with their breeding range extending across Asia as far as Japan, and a wintering range in sub-Saharan Africa and southern Asia. The bird stuck around for two days giving some excellent close views for visitors in the area around the Carneddau hide and over the lagoons. Another Alpine swift also made a brief appearance on 14/4, apparently a first summer bird with a rather ‘sooty’ appearance on the underparts rather than the large clean white patch seen on adults. Interestingly a bird seen four days later on Bardsey Island was thought to be the same individual.
More warblers continued to arrive with the first reed warbler appearing on 10/4, sedge warbler on 12/4, lesser whitethroat on 15/4, and common whitethroat on 23/4. Up to three Cetti’s warbler have also been heard singing around the reserve, some of which were present over the winter.
Other notable migrant passerines have included grasshopper warbler recorded on eight dates between 9/4 and 27/4 with a maximum of four birds heard on 23/4, tree pipit over on 12/4 and 16/4, up to three whinchat seen on four dates between 19/4 and 25/4, individual yellow wagtail on four dates between 18/4 and 5/5, and single redstarts on 21/4 and 26/4. Wheatear have also been regular, mostly seen along the estuary track, and white wagtails, the continental race of pied wagtail, have been very numerous. Unusually common swift were not the last of the summer migrants to be recorded this year, with at least one reported briefly in the company of the Alpine swift on 14/4 which is our earliest record to date, though they weren’t seen again until 28/4 when larger numbers began to appear.
Its been another good spring for ospreys with seven more records of individual birds flying over the reserve during the past month, while a female marsh harrier on 20/4 was also a good record here. Red kite were also seen over the reserve on six dates.
Sandwich terns have been seen regularly since 11/4 with a maximum count of 22 birds on 23/4. Most sightings have occurred over the estuary, with occasional birds coming on to the lagoons and some mating behavior observed, though its very unlikely they would breed here. There have also been further appearances from yellow-legged gulls, with four sightings between 9/4 and 2/5.
Wader passage has been interesting with a variety of species seen including further spotted redshank recorded on six dates including two birds on 5/4, individual little ringed plover on five dates from 8/4, a single turnstone on 16/4 which are surprisingly scarce on the reserve, greenshank on three dates including two present on 18/4, ringed plover also on three dates with a maximum of eight birds on 23/4, individual knot on 23/4 with a further two on 5/5, and bar-tailed godwit on 23/4 and 2/5. More regular passage waders have included small numbers of black-tailed godwit with a maximum of nine birds on 23/4, whimbrel since 9/4 with a maximum count of 10 on 5/5, and dunlin with a peak count of 46 on 4/5. Common sandpiper have also been present in good numbers with a maximum of 10 on 4/5.
Notable wildfowl and other water birds have included the long staying female scaup which made two further brief appearances on 10/4 and 16/4 before disappearing, and merganser on several dates with a maximum of nine on 5/4, while a pair of wigeon were seen on 23/4 with a single drake still present up until at least 6/5. A pair of great crested grebe remain on the deep lagoon and were joined by a third bird on 6/4, while feral species have included a drake mandarin on 19/4 and two barnacle geese which were present from 27/4 to 28/4.
Invertebrates have included increasing numbers of butterflies with comma and speckled wood (pictured) recorded since 4/4, orange tip and green-veined white since 15/4, holly blue and small tortoiseshell since 26/4, and brimstone since 2/5. A large red damselfly on 5/5 was the first odonata species recorded this year, while a 22-spot ladybird was only the second record for the reserve, and a water scorpion found in the dipping pond was also notable with just three previous records here.
A day time sighting of an otter in the deep lagoon on 24/4 was also of interest.