Wednesday 5 December 2018

Corvo 2018 – Another bonanza autumn on the Rock!

I managed to compile a summary of observations and a few descriptive stats for the past autumnal season on Corvo.

A summary table of all individual records is presented below. The table focuses on species/individuals of Nearctic origin. In addition to those records, quite an impressive tally of Palearctic species were also reported, including some incredible records such as a Red-breasted Flycatcher and multiple Yellow-browed Warblers…

This year, an estimated 100+ birders visited this tiny island from mid-September to early November. The first Nearctic waterbird species was found on 12/09 (White-rumped Sandpiper) and the last one on 03/11 (American Bittern), while for Nearctic landbirds the season was less protracted with the first species found on 04/10 (Northern Harrier) and last on 24/10 (Magnolia Warbler).

Overall, no less than 29 American landbird species were reported, with a total estimated 102 different individuals. Thus, in terms of species richness, 2018 was as good as 2017 – and together those are the best two years ever experienced on Corvo! In addition, 13 American Waterbird species were found during the autumn, with a total estimated 30 different individuals, which sets 2018 as an average year for waterbirds.

As can be seen from the two graphs below, most Nearctic landbird rarities were produced over the week 16-23 October. That week will probably remain in everyone’s memory (at least for those lucky birders present on the island!), particularly 16-17 October with 31 and 37 landbird individuals reported respectively, of which 22 and 20 were new findings for the day.

Daily totals of Nearctic individuals reported on Corvo (daily totals include both new birds for the day and birds found on a previous day and still present)
Cumulative plot of Nearctic landbird individuals discovered on Corvo, 4-29 October 2018 (n = 102 records)
Quality was also at the rendez-vous this year with a long list of extremely rare records for the Western Palearctic (WP): Blue Grosbeak (1st WP record); Eastern Wood Pewee (3rd WP record); Bay-breasted Warbler (3rd WP record); Wilson's Warbler (4th WP record; first for Azores); White-eyed Vireo (4th WP record); Lincoln's Sparrow (5th WP record); Wood Thrush (5th WP record); Yellow-throated Vireo (8th WP record), etc.

White-eyed Vireo, 4th WP record (all 4 records are from Corvo), 20 October 2018 (David Monticelli)
A more complete account is currently in prep for publication on Birdguides in the next days!