7 thoughts on “Striated Caracara (Phalcoboenus australis)”
Hello!
I really applaud the initiative of reassesing this species! However, I have some concerns that I’d like to share.
Since the last cited published paper (Reeves et al. 2018), several publications have addressed the species’ distribution, abundance, and threats. Importantly, this species has been shown to occur in very scattered, fragmented populations, with very limited dispersal (and thus gene flow) among them, due to the extreme philopatry of its individuals. The distribution map also looks misleading: this is a marine island raptor, rarely observed > 500 m from the coast. Actually, most of the islands it occupies are too small to be visible on the distribution map, meaning both EOO and AOO are likely even more overestimated than in previous assessments.
Overall, the more we learn about the Striated Caracara, the more concerned we become, and this reassessment does not seems to reflect the current state of knowledge of the species.
I’d like to add my concern regarding the limited scope of the reassessment. Specifically the reassessment neglects two key manuscripts that provide data directly relevant to the IUCN assessment criteria.
Mature Individuals: Balza et al. 2024 found that breeding adults represented only 6–15% of the population on Isla de los Estados. Furthermore, they found variablility in territory occupancy and hatching rate and sex biased chick ratios. Under these conditions, according to the IUCN guidelines (found here https://portals.iucn.org/library/sites/library/files/documents/RL-2001-001-2nd.pdf), the lower estimate of mature individuals should be used in assessing population size (in this case 354 pairs, Reeves et al. 2018). This suggests a much lower population estimate than what’s currently stated in the reassessment.
Subpopulations/Severely Fragmented: Balza et al. 2025 identified divergent lineages between the mainland South American population and the Falkland Islands population (i.e., no genetic flow, and thus smaller isolated subpopulations). Even within the Falkland Islands, the research found genetic structure, which matches the limited inter-island movement by established breeding pairs (Harrington, unpublished data). These subpopulations, particularly because they are high density within restricted coastal ranges, are thus at higher extinction risk than they otherwise would be.
Given the omission of these critical data, I suggest this has not been a proper reassessment of the species’ status. Combined with the deficiency of data regarding other relevant criteria, I highly encourage the committee to reconsider the delisting, and at the very least, redo the reassessment taking into account this new information.
Thank you for your time,
Dr. Katie Harrington
Balza, Ulises, et al. “Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor.” Ibis 166.2 (2024): 504-517.
Balza, Ulises, et al. “Glacial History and Ecological Restrictions Shape Island‐Scale Genetic Structure and Demography in the Southernmost Bird of Prey.” Journal of Biogeography (2025).
Alongside the previous 2 commentors that address concerns on the scope of the assessment, in particular, the population distribution and rationale of the estimated population size, there is also a general absence in addressing the most current and relevant threats to the species.
Wildfires:
In the last 5 years there has been a significant increase in wildfires from lightning strikes at offshore tussac islands at the Falklands, including Bird Island (55 breeding pairs), Grand Jason (96 breeding pairs) and Sea Lion Island (17 breeding pairs in 2013 surveys). Fire damage on offshore tussac islands (favoured habitat of SC) significantly reduces prey availability. At Bird Island there was an estimated 600,000 pairs of thin-billed prions, an important food source of the species. Peat fires are one of the most destructive types of fires known as they destroy surface vegetation but also smoulder underground for many years destroying burrowing seabird nesting habitat. It is likely that with an increasingly drying climate at the Falklands and increased lightning storms, fire damage to breeding habitat of striated caracara will increase. There is no current data to understand how fire events could impact the population structure of a highly territorial species through loss of breeding habitat and critical food sources.
Disease:
Avian influenza (H5N1) has been present at the Falklands since September 2024 to present, detected island wide. The majority of fatalities to date have been observed in gentoo penguin and black-browed albatross (food sources). Fatalities in seabird scavengers, although low have been reported (inc. Striated Caracara). The impact of H5N1 directly and/or indirectly through reduced long-term food sources (seabirds, seals) and impacts on chick survival of striated caracara receiving infected food is currently unknown. The presence of H5N1 at the Falklands is on-going and trajectory and evolution unknown.
The combined comments received indicate that those actively involved in researching and understanding this species highly encourage the committee to reconsider the delisting and amend the assessment, especially under the current climate of threats that exist through their breeding range.
Best wishes
Sarah Crofts and Micky Reeves, Falkland Islands
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 25 April 2025. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 25 April 2025, when discussions will re-open.
We thank all those who have contributed valuable information, including that sent via email by J. Meiburg, all of which has been incorporated into the updated Red List assessment for this species. The published map will be adjusted in response to the comments made. Given evidence of divergent lineages between the mainland and Falkland Islands populations, and genetic structure even within the Falkland Islands (Balza et al. 2025), it is considered plausible that the largest subpopulation may number less than 1,000 mature individuals. Additionally, on a precautionary basis, the population trend is suspected to be decreasing due to the ongoing threats. Based on available information therefore, our preliminary proposal for the 2025 Red List would be to list Striated Caracara as Near Threatened, approaching thresholds under Criterion C2a(i).
There is now a period for further comments until the final deadline on 4 May 2025, after which the recommended categorisations will be put forward to IUCN.
The final 2025 Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 12 May 2025.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Striated Caracara is recommended to be listed as Near Threatened, approaching thresholds under Criterion C2a(i).
Many thanks for everyone who contributed to the 2025.2 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Hello!
I really applaud the initiative of reassesing this species! However, I have some concerns that I’d like to share.
Since the last cited published paper (Reeves et al. 2018), several publications have addressed the species’ distribution, abundance, and threats. Importantly, this species has been shown to occur in very scattered, fragmented populations, with very limited dispersal (and thus gene flow) among them, due to the extreme philopatry of its individuals. The distribution map also looks misleading: this is a marine island raptor, rarely observed > 500 m from the coast. Actually, most of the islands it occupies are too small to be visible on the distribution map, meaning both EOO and AOO are likely even more overestimated than in previous assessments.
Overall, the more we learn about the Striated Caracara, the more concerned we become, and this reassessment does not seems to reflect the current state of knowledge of the species.
Best,
Ulises
I’d like to add my concern regarding the limited scope of the reassessment. Specifically the reassessment neglects two key manuscripts that provide data directly relevant to the IUCN assessment criteria.
Mature Individuals: Balza et al. 2024 found that breeding adults represented only 6–15% of the population on Isla de los Estados. Furthermore, they found variablility in territory occupancy and hatching rate and sex biased chick ratios. Under these conditions, according to the IUCN guidelines (found here https://portals.iucn.org/library/sites/library/files/documents/RL-2001-001-2nd.pdf), the lower estimate of mature individuals should be used in assessing population size (in this case 354 pairs, Reeves et al. 2018). This suggests a much lower population estimate than what’s currently stated in the reassessment.
Subpopulations/Severely Fragmented: Balza et al. 2025 identified divergent lineages between the mainland South American population and the Falkland Islands population (i.e., no genetic flow, and thus smaller isolated subpopulations). Even within the Falkland Islands, the research found genetic structure, which matches the limited inter-island movement by established breeding pairs (Harrington, unpublished data). These subpopulations, particularly because they are high density within restricted coastal ranges, are thus at higher extinction risk than they otherwise would be.
Given the omission of these critical data, I suggest this has not been a proper reassessment of the species’ status. Combined with the deficiency of data regarding other relevant criteria, I highly encourage the committee to reconsider the delisting, and at the very least, redo the reassessment taking into account this new information.
Thank you for your time,
Dr. Katie Harrington
Balza, Ulises, et al. “Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor.” Ibis 166.2 (2024): 504-517.
Balza, Ulises, et al. “Glacial History and Ecological Restrictions Shape Island‐Scale Genetic Structure and Demography in the Southernmost Bird of Prey.” Journal of Biogeography (2025).
Alongside the previous 2 commentors that address concerns on the scope of the assessment, in particular, the population distribution and rationale of the estimated population size, there is also a general absence in addressing the most current and relevant threats to the species.
Wildfires:
In the last 5 years there has been a significant increase in wildfires from lightning strikes at offshore tussac islands at the Falklands, including Bird Island (55 breeding pairs), Grand Jason (96 breeding pairs) and Sea Lion Island (17 breeding pairs in 2013 surveys). Fire damage on offshore tussac islands (favoured habitat of SC) significantly reduces prey availability. At Bird Island there was an estimated 600,000 pairs of thin-billed prions, an important food source of the species. Peat fires are one of the most destructive types of fires known as they destroy surface vegetation but also smoulder underground for many years destroying burrowing seabird nesting habitat. It is likely that with an increasingly drying climate at the Falklands and increased lightning storms, fire damage to breeding habitat of striated caracara will increase. There is no current data to understand how fire events could impact the population structure of a highly territorial species through loss of breeding habitat and critical food sources.
Disease:
Avian influenza (H5N1) has been present at the Falklands since September 2024 to present, detected island wide. The majority of fatalities to date have been observed in gentoo penguin and black-browed albatross (food sources). Fatalities in seabird scavengers, although low have been reported (inc. Striated Caracara). The impact of H5N1 directly and/or indirectly through reduced long-term food sources (seabirds, seals) and impacts on chick survival of striated caracara receiving infected food is currently unknown. The presence of H5N1 at the Falklands is on-going and trajectory and evolution unknown.
The combined comments received indicate that those actively involved in researching and understanding this species highly encourage the committee to reconsider the delisting and amend the assessment, especially under the current climate of threats that exist through their breeding range.
Best wishes
Sarah Crofts and Micky Reeves, Falkland Islands
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 25 April 2025. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 25 April 2025, when discussions will re-open.
Preliminary proposal
We thank all those who have contributed valuable information, including that sent via email by J. Meiburg, all of which has been incorporated into the updated Red List assessment for this species. The published map will be adjusted in response to the comments made. Given evidence of divergent lineages between the mainland and Falkland Islands populations, and genetic structure even within the Falkland Islands (Balza et al. 2025), it is considered plausible that the largest subpopulation may number less than 1,000 mature individuals. Additionally, on a precautionary basis, the population trend is suspected to be decreasing due to the ongoing threats. Based on available information therefore, our preliminary proposal for the 2025 Red List would be to list Striated Caracara as Near Threatened, approaching thresholds under Criterion C2a(i).
There is now a period for further comments until the final deadline on 4 May 2025, after which the recommended categorisations will be put forward to IUCN.
The final 2025 Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 12 May 2025.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Striated Caracara is recommended to be listed as Near Threatened, approaching thresholds under Criterion C2a(i).
Many thanks for everyone who contributed to the 2025.2 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.