TicoTyler
Tyler Wenzel
The latest guide to the birds of Costa Rica came out last year (2023) and I've been meaning to take the time to write up something about it for a while, particularly about a handful errors in the text. Like most field guides it is evidently a labor of love and no one is getting rich off of writing bird books. What I lay out here, alongside some brief highlights of things I enjoy, is meant to clarify some of the mistakes in the book for the reader. Above all guides need to be accurate and hopefully, as I've not found a way to contact either author (feel free to reach out to me, I'd love to help out on future editions!), they can be incorporated into a second edition. I've tried to avoid nitpicking in areas where a judgment call could be made either way on a topic.
Positive Aspects of the Book
Before detailing some criticisms I wanted to first acknowledge the things I enjoyed about this book. As always, Dale Dyer's artwork is superb. In particular, the inclusion of juvenile plumages, molts, and some sub-species provides more detail and is incredibly helpful. In this aspect, the book is currently the best illustrated of the three guides to Costa Rica. (Dyer also illustrated the Birds of Central America which is fantastic but not as specific to Costa Rica.) I found the descriptions to be concise, easy to read (including the font choice, not just readability) and helpful, with only a handful of errors that I want to detail below. The novel taxonomy is at least thought-provoking if debatable at times (which is the point of including it) but that is an entirely different subject. I personally like the wider exposure it gives to systematics than other books, but I have talked to many people who are against it. This is one of those judgment calls/personal preference matters I don't address in this post.
Errors with Ranges
The book starts with a particularly odd error in its introduction. On page 10 there is a note on eBird reports and how they can be problematic for determining ranges. I wholeheartedly agree with the sentiment and they are correct in this claim. But they then chose to illustrate this fact with a species they are just plain wrong about. They claim that Groove-billed Anis categorically do not occur in the Pacific South of Costa Rica and that the few alleged images of them in the Pacific South are all Smooth-billed Anis. I will say that they are not entirely wrong. The images that they looked at in 2021 based on the date in Figure 4 probably were mistaken as they are no longer on eBird. However, there are images from 2022 that show a Groove-billed Ani at Esquinas Rainforest Lodge and there are past reports by local experts (guides/eBird reviewers) who have seen the species in the South Pacific. I believe this, and the description of the species on page 172 where they claim it is "absent" from the S. Pacific Lowlands is a result of the fact that unlike the guides by Stiles & Skutch and Garrigues & Dean, both Dyer and Howell are occasional visitors to Costa Rica having spent "many months" (pg. 6) in the country not decades like the other authors whose range descriptions tend to be more accurate (see Garrigues & Dean who list the species as "rare in the South Pacific" which is the correct description.)
Other errors include Northern Potoo whose range map shows it extending up into the Central Valley but it does not extend there; it stops around Carara/Tarcoles/Jaco. The Maroon-chested Ground-Dove is showed as extending up into the Tilarán and Guanacaste mountains when it has only been reported in the Central and Talamanca mountains. The Tricolored Munia is (rarely) found on the Caribbean slope (the text only refers to the Pacific, it does mention its range was expanding, but by 2022 there were already over a dozen reports on the Caribbean slope).
Errors with Frequency
On a related topic, the determination of how common a bird is can be quite subjective and variable. However, there is some internal inconsistency in the text around several species I'd like to point out. Their scale is listed as being:
This is true of the Pacific slope but on the Caribbean slope, it is almost unheard of. There are a few reports from around the La Selva (Sarapiqui) area with documentation in 2014 and a small handful of more recent reports that are reliable but without documentation. On the Caribbean slope, it should qualify as "Rare" at best, not "uncommon to fairly common". It has only been sighted on average about once per year over the last years on the Caribbean side of the country.
Harpy Eagle: I agree that it is "very rare" but it says on both the Caribbean slope and S. Pacific. This is one that is debatable but I think it would benefit from being clearer in its text. It has been seen a handful of times on the Caribbean slope in the last two decades. It has not been seen in the S. Pacific in 23 years. It definitely could still be found in the interior Talamancas or some unvisited corner of the Osa Peninsula, but it would be clearer to be more explicit about just how unexpected this species is given that many tourists still think they have a decent chance at seeing this bird in Corcovado and some unscrupulous tour operators even advertise there being a "small population" of it there (not to give them revenue, but one example for proof).
Rock Wren: This one is listed as "uncommon and local" despite the fact it has only been reported twice in recent decades, both without documentation although at least in one case by a very reliable source (Jim Zook), in the last 20 years. Once in 2004 (Zook) and again in 2016 that was only IDd by audio/playback but not seen. Both times in the same location (Rincón de la Vieja). That should be listed as "Very rare" not "Uncommon".
Yellow-throated Euphonia: This is one of the most baffling errors. It is listed as "scarce to locally uncommon (increasing?) on Caribbean slope and s. Pacific slope." This is one of the most common birds on the Caribbean Slope. For example, the most birded hot spot in the country, the Arenal Observatory Lodge, shows it on 40% of all checklists and it's the 25th most common bird reported there. Yet somehow it's considered rarer than the "uncommon" Rock Wren that has been seen once a decade? My only thought is that there was some kind of typo here and the scarce part was supposed to just apply to the s. Pacific slope as it is extremely rare there with only three photos south of Tarcoles.
Errors with Historical Reports
Tropical Mockingbird: As I detailed in a post here on the forum about the historical range of the Tropical Mockingbird in southern Central America, the book claims it was first seen in 2000. I think this is a misunderstanding of Garrigues & Dean saying "Since the turn of the century, has become widespread" which was a comment on how abundant it had grown in recent years vs its uncommon status when Stiles & Skutch included it not when it first started establishing itself in the 1980s. A specimen (almost definitely an escaped caged bird) was collected by Zeledón near Zarcero in 1887; by the time the first modern field guide came out in the late 80s (Stiles & Skutch) it was already being sporadically reported in the country, well before 2000.
White-tailed Kite: It says it was first reported in the late 1950s. This seems to be based on a misunderstanding of Slud (1964) who said:
Some Misc. Typos & Observations
I won't go into much detail here, just some small proofreading issues or things I wanted to comment on.
White-throated Crake (pg 92) - the text talks about the "Rusty-faced" subspecies but the label on the range map says "Rust-faced".
Professional Antbirds header (pg 268) - says 3 species but there are 7 in the section. Three on the page the header is on but four more on the next page.
Brown Booby Complex - This one was split as they imagined with their taxonomy. I just thought it was odd that given they were previously the same species the two "Brown" Boobies got put on different plates. Maybe there's a reason for it, just not sure why.
Tahiti Petrel - This is a judgement call and very minor but it seems the Tahiti Petrel is turning out to be much more common in nearish (10-20 mile) shore waters than expected. It seems anymore most pelagic trips out of Cabuya sight at least one. The text doesn't really refer to it as rare or say it doesn't come that close, just it is a a species that I think is generally more common in not too far offshore waters than any of the field guides give the impression. Whether this is a new development or has always been this way is debated.
Positive Aspects of the Book
Before detailing some criticisms I wanted to first acknowledge the things I enjoyed about this book. As always, Dale Dyer's artwork is superb. In particular, the inclusion of juvenile plumages, molts, and some sub-species provides more detail and is incredibly helpful. In this aspect, the book is currently the best illustrated of the three guides to Costa Rica. (Dyer also illustrated the Birds of Central America which is fantastic but not as specific to Costa Rica.) I found the descriptions to be concise, easy to read (including the font choice, not just readability) and helpful, with only a handful of errors that I want to detail below. The novel taxonomy is at least thought-provoking if debatable at times (which is the point of including it) but that is an entirely different subject. I personally like the wider exposure it gives to systematics than other books, but I have talked to many people who are against it. This is one of those judgment calls/personal preference matters I don't address in this post.
Errors with Ranges
The book starts with a particularly odd error in its introduction. On page 10 there is a note on eBird reports and how they can be problematic for determining ranges. I wholeheartedly agree with the sentiment and they are correct in this claim. But they then chose to illustrate this fact with a species they are just plain wrong about. They claim that Groove-billed Anis categorically do not occur in the Pacific South of Costa Rica and that the few alleged images of them in the Pacific South are all Smooth-billed Anis. I will say that they are not entirely wrong. The images that they looked at in 2021 based on the date in Figure 4 probably were mistaken as they are no longer on eBird. However, there are images from 2022 that show a Groove-billed Ani at Esquinas Rainforest Lodge and there are past reports by local experts (guides/eBird reviewers) who have seen the species in the South Pacific. I believe this, and the description of the species on page 172 where they claim it is "absent" from the S. Pacific Lowlands is a result of the fact that unlike the guides by Stiles & Skutch and Garrigues & Dean, both Dyer and Howell are occasional visitors to Costa Rica having spent "many months" (pg. 6) in the country not decades like the other authors whose range descriptions tend to be more accurate (see Garrigues & Dean who list the species as "rare in the South Pacific" which is the correct description.)
Other errors include Northern Potoo whose range map shows it extending up into the Central Valley but it does not extend there; it stops around Carara/Tarcoles/Jaco. The Maroon-chested Ground-Dove is showed as extending up into the Tilarán and Guanacaste mountains when it has only been reported in the Central and Talamanca mountains. The Tricolored Munia is (rarely) found on the Caribbean slope (the text only refers to the Pacific, it does mention its range was expanding, but by 2022 there were already over a dozen reports on the Caribbean slope).
Errors with Frequency
On a related topic, the determination of how common a bird is can be quite subjective and variable. However, there is some internal inconsistency in the text around several species I'd like to point out. Their scale is listed as being:
Paint-billed Crake: "Uncommon to fairly common locally on both slopes, to 1000m"
This is true of the Pacific slope but on the Caribbean slope, it is almost unheard of. There are a few reports from around the La Selva (Sarapiqui) area with documentation in 2014 and a small handful of more recent reports that are reliable but without documentation. On the Caribbean slope, it should qualify as "Rare" at best, not "uncommon to fairly common". It has only been sighted on average about once per year over the last years on the Caribbean side of the country.
Harpy Eagle: I agree that it is "very rare" but it says on both the Caribbean slope and S. Pacific. This is one that is debatable but I think it would benefit from being clearer in its text. It has been seen a handful of times on the Caribbean slope in the last two decades. It has not been seen in the S. Pacific in 23 years. It definitely could still be found in the interior Talamancas or some unvisited corner of the Osa Peninsula, but it would be clearer to be more explicit about just how unexpected this species is given that many tourists still think they have a decent chance at seeing this bird in Corcovado and some unscrupulous tour operators even advertise there being a "small population" of it there (not to give them revenue, but one example for proof).
Rock Wren: This one is listed as "uncommon and local" despite the fact it has only been reported twice in recent decades, both without documentation although at least in one case by a very reliable source (Jim Zook), in the last 20 years. Once in 2004 (Zook) and again in 2016 that was only IDd by audio/playback but not seen. Both times in the same location (Rincón de la Vieja). That should be listed as "Very rare" not "Uncommon".
Yellow-throated Euphonia: This is one of the most baffling errors. It is listed as "scarce to locally uncommon (increasing?) on Caribbean slope and s. Pacific slope." This is one of the most common birds on the Caribbean Slope. For example, the most birded hot spot in the country, the Arenal Observatory Lodge, shows it on 40% of all checklists and it's the 25th most common bird reported there. Yet somehow it's considered rarer than the "uncommon" Rock Wren that has been seen once a decade? My only thought is that there was some kind of typo here and the scarce part was supposed to just apply to the s. Pacific slope as it is extremely rare there with only three photos south of Tarcoles.
Errors with Historical Reports
Tropical Mockingbird: As I detailed in a post here on the forum about the historical range of the Tropical Mockingbird in southern Central America, the book claims it was first seen in 2000. I think this is a misunderstanding of Garrigues & Dean saying "Since the turn of the century, has become widespread" which was a comment on how abundant it had grown in recent years vs its uncommon status when Stiles & Skutch included it not when it first started establishing itself in the 1980s. A specimen (almost definitely an escaped caged bird) was collected by Zeledón near Zarcero in 1887; by the time the first modern field guide came out in the late 80s (Stiles & Skutch) it was already being sporadically reported in the country, well before 2000.
White-tailed Kite: It says it was first reported in the late 1950s. This seems to be based on a misunderstanding of Slud (1964) who said:
So while Slud first saw it in 1958 he also reported that locals were very familiar with the bird and it was regular in certain regions of the country. It probably has expanded with habitat disruption as claimed, but like with the Mockingbird it has been along for considerably longer than the book claims.
Some Misc. Typos & Observations
I won't go into much detail here, just some small proofreading issues or things I wanted to comment on.
White-throated Crake (pg 92) - the text talks about the "Rusty-faced" subspecies but the label on the range map says "Rust-faced".
Professional Antbirds header (pg 268) - says 3 species but there are 7 in the section. Three on the page the header is on but four more on the next page.
Brown Booby Complex - This one was split as they imagined with their taxonomy. I just thought it was odd that given they were previously the same species the two "Brown" Boobies got put on different plates. Maybe there's a reason for it, just not sure why.
Tahiti Petrel - This is a judgement call and very minor but it seems the Tahiti Petrel is turning out to be much more common in nearish (10-20 mile) shore waters than expected. It seems anymore most pelagic trips out of Cabuya sight at least one. The text doesn't really refer to it as rare or say it doesn't come that close, just it is a a species that I think is generally more common in not too far offshore waters than any of the field guides give the impression. Whether this is a new development or has always been this way is debated.
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