April and May are always exciting months for birders with the joy of seeing returning migrants and the chance of seeing something  really unusual. Birders are active and as usual we received many reports of sightings. Overall coverage, particularly in the mountains, was down on previous years, partly because there was no Boulder County Birdathon this year, although several observers held their own versions of “big days”. This year shorebird migration seems to have been strong with the only common species  missed being Western Sandpiper. Unusual species included Black-bellied Plover, Black-necked Stilt, Whimbrel, Ruddy Turnstone (last seen in 2004), White-rumped Sandpiper (last seen in 2003), Stilt Sandpiper (2003), and Red-necked Phalarope. The Boulder Reservoir area seemed particularly productive for shorebirds. The number of warbler species was low (sixteen) but included Blue-winged Warbler (last seen in 2004), Northern Parula, at least three Black-throated Gray Warblers, Blackpoll Warbler, Black-and-White Warbler (last seen in 2004), Ovenbird, and Worm-eating Warbler (last seen in 2002).

By the end of the first week of May duck numbers had decreased dramatically with only a few stragglers lingering into the second week. There were enough reports at Walden Ponds to track the daily decline of such species as Gadwall and American Wigeon. Cattle Egret was reported for the first time since 2004. White-faced Ibis arrived in the county in huge numbers on April 17 - I had hoped to tie this arrival in with the passing of a cold front but unfortunately can see no such evidence as this entire period was warmer and drier than normal. One Glossy Ibis was reported at this time.

Other less usual species included a Caspian Tern seen at Walden Ponds and last reported in the county in 2002. Barn Owls are known to be nesting in several locations. Black-chinned Hummingbirds were reported in north Boulder; these birds are more usually seen in August during fall migration. An Eastern Phoebe was the fifth record for the county and also last seen in 2002. Three separate Gray Flycatchers were seen. Brown Thrasher was reported both months after a gap of a year. An Eastern Towhee has apparently been wintering in a north Boulder yard; this is only the second report of this species to the inventory. The previous sighting was in December 1999.

For the highest number of bird species to be seen in May, both shorebird and warbler migration needs to be strong and overall coverage needs to be excellent so that no common species are missed. While May 2006 certainly did not meet all these criteria, and was nowhere near the record number of 243 species seen in May 2002,  the 218 bird species reported to the inventory made for a respectable list. In addition 154 bird species were reported to the inventory in April. TOP