The month opened with a mini Indian summer, long sunny and hot days prevailed with daytime peak temperatures reaching the mid-20s Celsius. The drought dragged on and the effects of four months without rain became ever more apparent in the levels of water in the ponds on the park. The vegetation and the trees started to lose their leaves early. The hot spell broke on 22 September with the southerly passage of a frontal system, which brought five hours of heavy rain and introduced a period of cool north-westerly winds.
Highlights of the month started with a Little Egret flapping low over the northern park at 8.05am hours on 2 September before eventually continuing west and over the Humber Bridge approach road. This was the third record of this southern heron in the park, with the previous two occurring on 3 October 2000 and on 31 May 2001.
A juvenile Hobby took a Migrant Hawker ten metres in front of observers on 20 September. It then plucked off and discarded the wings before eating it on the wing, all in full view in bright sunshine. For sheer aesthetics, this took some beating! With the abundant population of Migrant Hawkers, this species may hopefully become more regular on the complex in future.
Up to three Peregrines were also to be seen overhead in the first two weeks, with a fine juvenile over the Middle Lagoon on 9 September. A new bird for the park, a juvenile Arctic Tern dropped in onto the largest northern pond on the morning of 26 September. It stayed long enough for a short sleep as it perched on the newly created delta area.
August was not a startling month for wader passage, but September opened well with a juvenile Knot flying over the northern park on 2 September, to be followed by a juvenile Ruff on 3 September. Pride of place in the first week went to two Curlew Sandpipers, the first record for the park, which were present for about an hour on the morning of 3 September. One was a pristine juvenile and the other a moulting adult which sadly had a rather badly injured leg. The roost of Redshank totalled 22 birds in the first week, while the Green Sandpiper continued to commute between the new lagoons and the remnants of the water at the southern end of the Middle Lagoon.
Curlew Sandpipers became almost commonplace later in the month with a peak of three juveniles roosting on 22 September along with the first juvenile Little Stint of the year. Both of these species breed in the tundra of northern Siberia and migrate in winter to Africa via a south-westerly route, which brings them through Western Europe. Their numbers vary annually, depending upon breeding success and the direction of the prevailing winds. Odd Black-tailed Godwits also made occasional visits to the pools with a regular small flock feeding on the adjacent foreshore.
Good numbers of Teal were migrating west up the Humber during the month, with peak counts of over 400 birds on some days in the first week. Several of the flocks passed over the park as they attempted to find the lowest and safest route over the Humber Bridge. A few landed on the Middle Lagoon and the eastern site of special scientific interest (SSSI), where a small feeding flock developed late in the month, peaking at 32 birds. Accompanying them were two Garganey on 15 September and one of these stayed on the eastern SSSI to 22 September. Garganey are a scarce autumn migrant to the area with most being recorded in August, so these two birds were making a late stay, no doubt influenced by the hot weather. Other wildfowl in good number included Gadwall with 45 on the eastern SSSI mid-month, Little Grebe maximum 22 birds and Moorhen of which there were 50 following a good breeding season.
The first wild geese of the autumn, Pink-footed Geese from Iceland, usually arrive on the Humber in the third week of September. The appearance of two flocks of 6 and 9 over the park on 20 September was a welcome sign of the return of this charismatic species. Of rather less interest to the purist was the first Egyptian Goose for the area that flew over the park on 17 September. This species is expanding its range from its original stronghold in North Norfolk where birds were first released from their native range in Africa.
Kingfishers were frequent visitors, with one or two most days and a maximum of four birds being logged. The first Grey Wagtails arrived with one on 9 September and 1-2 daily from 15 September, but a party of five Bearded Tits irrupting over the park on 18 September was only the second occurrence since 1994. The weedy areas on the northern site attracted a fine flock of finches in the first week, with a maximum of 122 Linnets being recorded along with Greenfinches and Goldfinches.
Most summer migrants had departed by the end of the first week but there was a late Swift over the park on 14 September, a Sedge Warbler on 19 September and a fine male Yellow Wagtail on 20 September. The exception was the number of House Martins, which usually peaks in September. This year was typical, with a flock of up to 200 birds noisily feeding over the park and resting on the telephone wires along Waterside road. Smaller numbers of Swallows accompanied them along with a few Sand Martins. Most Sand Martins had gone by the start of the month, with a late bird moving west on 20 September. On the same day, a Jay also moved west across the northern park hotly pursued by a large flock of hirundines. This species is not annual although they nest as close as Saxby.
A poor acorn crop in the autumn is usually the trigger for birds to move out from their favoured woods to search for winter food. This is when they appear in unusual locations. Good numbers of Chiffchaffs lingered through the month and the first Goldcrests passed through from 20 September. Another autumnal first was a fine female Stonechat on the northern park meadows from 24 to 26 September.
The warm weather in the first three weeks of the month produced a fine hatch of Comma butterflies. Three were seen on 3 September with up to eight individuals on some days later in the month, along with good numbers of Speckled Woods. Large and Small Whites were also still fairly common in the first week, along with Small Tortoiseshells and a good scatter of Red Admirals.
The late autumn heat benefited those dragonflies still on the wing, with large numbers of Migrant Hawkers and Common Darters seen daily. There were also a few Ruddy Darters in the first week and a Brown Hawker was seen near the Pasture Road hide 3 September, a fairly late date for this species in the area.