Summary of Peruvian Shorebird Census Results

Snowy Plover (Charadrius alexandrinus) at Paraiso, Peru, 11 Feb 2010.

During the first two weeks of February 2010, a coalition of groups, headed by the Cornell Lab of Ornithology, BirdLife Peru, Calidris (Colombia), Corbidi, Naturaleza y Cultura Internacional y Museo de Historia Natural de la UNSA and the U.S. Fish and Wildlife Service teamed up to hold a series of shorebird workshops and censuses at sites up and down the Peruvian coast. Nikon generously supported the effort by providing telescopes for use in the surveys. Each of three coastal regions—south, central, and north—hosted a daylong workshop covering the basics of shorebird identification and survey methodology lead by shorebird experts from around the Western Hemisphere.

On the following day or days, surveys were conducted at the various sites and was then input into the brand new eBird Peru portal. Below is a summary of the results. Morrison and Ross (1989. Atlas of Nearctic Shorebirds on the Coast of South America. Vols. 1 and 2, Can. Wildl. Serv. Spec. Publ., Ottawa) conducted aerial surveys of the Peruvian coast in February 1985 and those surveys have provided the best information available on shorebird populations in Peru. Part of the goal of this survey was to provide a ground-based perspective on those surveys and to provide a follow-up to see if any obvious changes had taken place.

A total of 150 people attended our shorebird workshops in Arequipa (Mejia Lagoons), Lima (Pantanos de Villa), and Piura (Manglares de San Pedro de Vice). We were overwhelmed with the high level of interest and knowledge from attendees, and are very grateful to all who attended and took part in the discussions and workshops in the field. Of the attendees, some 110 people participated on the surveys themselves, providing navigational help, expert local knowledge and logistical support as well as help with finding and identifying shorebirds, conducting surveys, and entering the data in eBird Peru.

Certain sites were clearly identified as highly important ones for shorebirds, given the large numbers of birds observed there. Paracas/Pisco, Estuario de Virrilá, and Manglares de San Pedro de Vice stood out as the very best sites, with large counts of shorebirds and high diversity as well. The best site in southern Peru was certainly the Lagunas de Ite, which were so large that our team was only able to survey a portion of the site. North of Lima, both Paraiso and Medio Mundo appear to harbor decent concentrations of shorebirds. Finally, two sites that turned out to be surprisingly good were Bahía Independencia/Laguna Grande and Humedales de Chancay, both of which produced quite high counts for a number of species.

Two people carrying scopes, walking on the beach

Fig. 1. Surveying shorebirds along the beach at Paraiso, Lima Dept., 11 Feb 2010. Photo by Marshall J. Iliff.

In total, we found 31 species of shorebirds on the surveys. Data are still being entered and proofed, but we can already report some of the initial findings, which we provide in the context of both Morrison and Ross (1989) and Schulenberg et al. (2007). Some of the observations of interest include:

  • We are very pleased that our counts of most species (except Sanderling, Calidris alba) are higher than those reported in Morrison and Ross (1989). The Peruvian coastline thus may be more important for shorebirds than previously thought, although clearly a ground-based approach will be more successful in detecting many species of shorebirds, especially in vegetated areas. This is certainly encouraging and highlights the ability of this study to help us better understand the shorebird populations in Peru.
Whimbrel on beach

Fig. 2. Whimbrel (Numenius phaeopus) at Paraiso, Lima Dept., Peru, 11 Feb 2010. Photo by Marshall J. Iliff.

  • Our counts of Whimbrel (Numenius phaeopus) were especially high, and some sites found flocks of up to several hundred (e.g., 985 at Estuario de Virrillá, Piura, 15 Feb 2010 and 450 at Paraiso, Lima, 11 Feb 2010).
  • A total of 55 Marbled Godwits (Limosa fedoa) were found at 3 locations. Schulenberg et al. (2007) consider this species “a rare boreal migrant in northwest; scattered records farther south”. Our records were as follows: one at Lagunas de Ite, Tacna, 7 Feb 2010 (photo below), apparently a first record for the department; one at Medio Mundo, Lima, on 11 Feb 2010; and 53 at Estuario de Virillá, Piura, which is just two short of the all-time high count for Peru (55 at the same location 27 Aug 2004). In adjacent Ecuador, Ridgely and Greenfield (2001. Birds of Ecuador) consider this species a casual vagrant in Ecuador.
Marbled Godwits wading

Fig. 3. Marbled Godwit (Limosa fedoa; center) at Lagunas de Ite 6 Feb 2010. This photo documents a new species for the Department of Tacna. How many other species are present? Photo by Richard Johnston.

  • A total of 15 Hudsonian Godwits (Limosa haemastica) were found at 6 locations. This species winters primarily in Chile, so the birds in Peru represent individuals at the northern edge of the range. Since the birds were all dull-plumaged, we believe they all represented first-winter birds. From south to north, the records included: Lagunas de Ite, Tacna (1; see above photo at bottom right), Lagunas de Mejia, Arequipa (two groups, 4 and 1), Humedales de Chancay, Lima (1), Paraiso, Lima (4; photo below), Estuario de Virillá, Piura (1), Manglares de San Pedro de Vice (3).
Hudsonian Godwits

Fig. 4. Hudsonian Godwits (Limosa haemastica) at Paraiso, Lima Dept., Peru, 11 Feb 2010. Photo by Marshall J. Iliff.

  • Collared Plovers (Charadrius collaris) were found farther south than mapped by Schulenberg et al. (2007), which shows their southern limit in northern Ancash. We had two sightings in the department of Lima on 11 Feb 2010, an agitated pair at Medio Mundo, two at the Río Supe, and one at Paraiso (photo below). It is not clear whether these birds might be resident or whether they were simply strays. The presence of two pairs, one behaving in an agitated and territorial fashion, suggests Medio Mundo/Río Supe are may be a possible breeding site.
Collared Plover

Fig. 5. Collared Plover (Charadrius collaris) at Paraiso, Lima Dept., Peru, 11 Feb 2010. This is south of the regular range and was the southernmost individual on our surveys. Photo by Marshall J. Iliff.

  • Short-billed Dowitcher (Limnodromus griseus) and Red Knot (Calidris canutus) were found in low numbers and restricted to the far north. The dowitchers that we found were all from Lambayeque north and the only high counts were from Bahía de Tumbes (120 on 15 Feb) and Manglares de San Pedro de Vice (70 on 13 Feb); it is unclear how regular this species is away from these areas and whether it regularly occurs farther south in winter or only as a migrant or stray. Red Knots were found only at Manglares de San Pedro de Vice (35 on 13 Feb and 23 on 14 Feb); this species apparently occurs only very locally in Peru in winter, although it may be more widespread as a migrant.
  • Shorebirds that favor rocky shorelines were extremely scarce on the surveys; although we tried to include appropriate habitat for censuses of rocky shorelines, access was often prohibitively difficult. Our totals for selected rocky specialists were Surfbird (Aphriza virgata; 1; Tacna), Wandering Tattler (Tringa incanus; 1; La Libertad), and Blackish Oystercatcher (Haematopus ater; 15 from 7 locations). The Surfbird total is especially disappointing since about 40% of the South American population is thought to winter in Peru. If you have observations of these three species from Peru, please enter then in eBird Peru!
  • Certain shorebirds that winter primarily in the interior of South America were recorded on the coast. These included American Golden-Plover (Pluvialis dominica; ~25 from ~10 locations), Baird’s Sandpiper (Calidris bairdii; ~4 from ~3 locations), Pectoral Sandpiper (Calidris melanotos; ~17 from ~6 locations), Stilt Sandpiper (Calidris himantopus; ~14 from 4 locations) and Wilson’s Phalarope (Phalaropus tricolor; 28 from 7 locations). All these species are mapped for these areas by Schulenberg et al. (2007), but based on our data, none could be considered particularly common.
  • Willet (Tringa semipalmata) was an interesting species. Not present at the majority of sites, large groups were found at San Pedro, Lima (300-600 total), Humedales de Chancay, Lima (600), Manglares de San Pedro de Vice (174), and Estuario de Virrillá (222). A few other counts of 25 or fewer were made at scattered locations in Tumbes and Piura. Clearly, the distribution of Willets on the Peruvian coast is quite spotty, but since Morrison and Ross (1989) totaled 588 Willets on their aerial surveys, these totals are a significant increase over their counts. Also of interest, was the fact that at least 35 at San Pedro de Vice, and most of the birds at Humedales de Chancay, could be identified as the western subspecies T. s. inornata. The subspecies composition of Willets in Peru has not been well-established, and specimens have been reported for both forms. However, it seems likely that only T. s. inornata occurs in Peru and our observations certainly suggest that form is the common one.
Western Willet

Fig. 6. Three ‘Western’ Willets (Tringa semipalmata inornata) at Manglares de San Pedro de Vice, Pirua Dept., Peru, 13 Feb 2010. The long necks, long legs, and long bills eliminate the similar T. s. semipalmata, which probably does not occur in Peru. Photo by Marshall J. Iliff.

Table 1. Species of shorebirds recorded on the Censos de Aves Playeras

1. Peruvian Thick-knee (Burhinus superciliaris)
2. Black-bellied Plover (Pluvialis squatarola)
3. American Golden-Plover (Pluvialis dominica)
4. Collared Plover (Charadrius collaris)
5. Snowy Plover (Charadrius alexandrinus)
6. Wilson’s Plover (Charadrius wilsonia)
7. Semipalmated Plover (Charadrius semipalmatus)
8. Killdeer (Charadrius vociferus)
9. American Oystercatcher (Haematopus palliatus)
10. Blackish Oystercatcher (Haematopus ater)
11. Black-necked Stilt (Himantopus mexicanus)
12. Spotted Sandpiper (Actitis macularius)
13. Greater Yellowlegs (Tringa melanoleuca)
14. Willet (Tringa semipalmata)
15. Lesser Yellowlegs (Tringa flavipes)
16. Wandering Tattler (Tringa incana)
17. Whimbrel (Numenius phaeopus)
18. Hudsonian Godwit (Limosa haemastica)
19. Marbled Godwit (Limosa fedoa)
20. Ruddy Turnstone (Arenaria interpres)
21. Surfbird (Aphriza virgata)
22. Red Knot (Calidris canutus)
23. Sanderling (Calidris alba)
24. Semipalmated Sandpiper (Calidris pusilla)
25. Western Sandpiper (Calidris mauri)
26. Least Sandpiper (Calidris minutilla)
27. Baird’s Sandpiper (Calidris bairdii)
28. Pectoral Sandpiper (Calidris melanotos)
29. Stilt Sandpiper (Calidris himantopus)
30. Short-billed Dowitcher (Limnodromus griseus)
31. Wilson’s Phalarope (Phalaropus tricolor)

In addition, the surveys turned up a number of interesting non-shorebird observations, all of which have been entered in eBird Peru. Perhaps foremost among these was a new species for Peru, a white morph Reddish Egret (Egretta rufescens) found and photographed by Marshall Iliff, Rebeca Alza, Ruth Cavero Contreras, Cecilia Gomez, and Cynthia Zurita at Boca del Rio Zaña. This exciting new record for Peru will be published separately elsewhere.

White morph Reddish Egret

Fig. 7. White morph Reddish Egret (Egretta rufescens) at Boca del Río Zaña, Lambayeque, Peru, on 14 Feb 2010. This individual represented the first record for Peru. Photo by Marshall J. Iliff.

Thanks to all those that participated on the surveys or otherwise assisted with this effort. We are very excited to have had the opportunity to have visited Peru, studied the shorebirds, and to have met so many great people. Our Atlas summarizing the complete results of the surveys will be published over the next year, and when it is, we will announce it here on eBird Peru.