7 thoughts on “Blue-headed Hummingbird (Riccordia bicolor)”
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 12 February 2024. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List status on this page on 12 February 2024, when discussions will re-open.
Based on available information, our preliminary proposal for the 2024 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 18 February 2024, after which the recommended categorisations will be put forward to IUCN.
The final 2024 Red List categories will be published on the BirdLife and IUCN websites in December 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.
First, I am very sorry not having been able to answer during the first period of consultation. Evolution of the LC category is very welcomed for this species of small AOO and EOO and subject to threats. Nevertheless, some proposed criteria did not take into account extensive surveys made in Martinique by Biotope (I have no link with them) and published (in French that is probably the reason) in 2014 (Dewynter et al. 2014) and 2017 that drive them to propose also EN at REGIONAL level. Nevertheless, their results conduct to correct the estimation of population . The current AOO in Martinique is between 100 and 160 km², that means 3 000 to 6 400 individuals (with 3-4 ind/km² that seems highly conservative and an under-estimation). The decrease of suitable habitat is estimated to 15 % in historical time (that is much more than 10 y or 3 generations). It is rightly raised that the climatic changes may increase strength of hurricanes in the future (the frequence is today hypothetical and challenged) but as this species is a species of altitude above 800 m (in Martinique), the increase of temperature has already a visible impact in the vegetation and will diminish the available favorable habitat. Hurricanes happen commonly in the Lesser Antilles and the biodiversity has some resilience to them. The 3 species of hummingbirds recovered quickly after hurricane Hugo in 1989 in Guadeloupe (the main difference was a huge increase of AOO of Eulampis jugularis !) It sems therefore that all the criteria are not met for EN at global level except if we take into account the increase of temperature (already 2 degrees in 40 y in the neighbouring Guadfeloupe) that will theorically increase the bottom altitude of the altitude ecosystem by around 400 m and therefore will decrease theorically the available favorable habitat by around 30 %.
Sorry. I made an big error in calculating the number of birds. by a factor of 10 ! It is possibly because the density of the bird was to increadibily low for my mind ( 3-4 birds/km²) . Estimation of density was much higher in Martinique during a survey made by de Mercey (AEVA) in 1996. I am looking for the report and come back with the right figure. Sorry again.
Following my precedent emails, I could read again the report made by Pierre de Mercey in 1966 (during his 8 months study on the evaluation of impact of a powerline project in Martinique). He could make an estimation of the relative density (it gives an idea of the magnitude allowing to compare species and habitat) of the bird species by point counts (80) with distance estimates (Bibby et al., 1993. Bird census techniques). The blue-headed humminbirds was the 7th most common bird with a density of 3,5 to 7,7 ind./ha in the favourable mountain (forest) habitat that is 100 times higher than the density used to make the redlist assessment. Even if the exact figure of the density may be discussed, the magnitude is here and an estimation of the number of birds in Martinique for 100 km² would be above 10 000 birds !!!!
De Mercey, P. 1996. Etude de l’avifaune sur l’aire du projet de la ligne EDF Saint Pierre / Le Marigot en périodes de reproduction et de migrations pré et post nuptiales (mi-février à mi-octobre 1996). PNR/EDF, 157p.
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 we will post a final decision on this species’ Red List status on this page on 26 February 2024.
Recommended categorisation to be put forward to IUCN
Following further review, the recommended categorisation for this species has been changed following helpful comments made by P. Feldmann that indicate the extinction risk of this species was overestimated by the proposal to list as Endangered. With density data that had been overlooked, the species’ global population size (probably greatly) exceeds 10,000 mature individuals, and therefore does not meet or approach the thresholds for listing as threatened under Criterion C or D(1). Because this species has demonstrated resistance and fast recovery to previous strong hurricanes, it is now considered that the number of Locations is probably >>10, even though the species is confined to only two islands. Threats are also not thought to be operating at an acuity and scale from which a continuing decline in AOO, EOO or mature individuals can be inferred. However, a decline in habitat extent and quality is precautionarily inferred given the threat of hurricanes and potentially climate change related altitudinal shifts in habitat. Accordingly, the species qualifies as only Near Threatened under Criterion B. The data in the original proposal for Criterion A is broadly accepted, although the rate of past decline is changed to 10-29% to reflect uncertainty over recovery time. Blue-headed Hummingbird is now recommended to be listed as Near Threatened, approaching the thresholds for listing as threatened under A2c+4c;B1b(iii).
Many thanks for everyone who contributed to the 2024.1 GTB Forum process. The final 2024 Red List categories will now be published on the BirdLife and IUCN websites in October 2024, 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 until 12 February 2024. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List status on this page on 12 February 2024, when discussions will re-open.
Preliminary proposal
Based on available information, our preliminary proposal for the 2024 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 18 February 2024, after which the recommended categorisations will be put forward to IUCN.
The final 2024 Red List categories will be published on the BirdLife and IUCN websites in December 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.
First, I am very sorry not having been able to answer during the first period of consultation. Evolution of the LC category is very welcomed for this species of small AOO and EOO and subject to threats. Nevertheless, some proposed criteria did not take into account extensive surveys made in Martinique by Biotope (I have no link with them) and published (in French that is probably the reason) in 2014 (Dewynter et al. 2014) and 2017 that drive them to propose also EN at REGIONAL level. Nevertheless, their results conduct to correct the estimation of population . The current AOO in Martinique is between 100 and 160 km², that means 3 000 to 6 400 individuals (with 3-4 ind/km² that seems highly conservative and an under-estimation). The decrease of suitable habitat is estimated to 15 % in historical time (that is much more than 10 y or 3 generations). It is rightly raised that the climatic changes may increase strength of hurricanes in the future (the frequence is today hypothetical and challenged) but as this species is a species of altitude above 800 m (in Martinique), the increase of temperature has already a visible impact in the vegetation and will diminish the available favorable habitat. Hurricanes happen commonly in the Lesser Antilles and the biodiversity has some resilience to them. The 3 species of hummingbirds recovered quickly after hurricane Hugo in 1989 in Guadeloupe (the main difference was a huge increase of AOO of Eulampis jugularis !) It sems therefore that all the criteria are not met for EN at global level except if we take into account the increase of temperature (already 2 degrees in 40 y in the neighbouring Guadfeloupe) that will theorically increase the bottom altitude of the altitude ecosystem by around 400 m and therefore will decrease theorically the available favorable habitat by around 30 %.
Sorry. I made an big error in calculating the number of birds. by a factor of 10 ! It is possibly because the density of the bird was to increadibily low for my mind ( 3-4 birds/km²) . Estimation of density was much higher in Martinique during a survey made by de Mercey (AEVA) in 1996. I am looking for the report and come back with the right figure. Sorry again.
Following my precedent emails, I could read again the report made by Pierre de Mercey in 1966 (during his 8 months study on the evaluation of impact of a powerline project in Martinique). He could make an estimation of the relative density (it gives an idea of the magnitude allowing to compare species and habitat) of the bird species by point counts (80) with distance estimates (Bibby et al., 1993. Bird census techniques). The blue-headed humminbirds was the 7th most common bird with a density of 3,5 to 7,7 ind./ha in the favourable mountain (forest) habitat that is 100 times higher than the density used to make the redlist assessment. Even if the exact figure of the density may be discussed, the magnitude is here and an estimation of the number of birds in Martinique for 100 km² would be above 10 000 birds !!!!
De Mercey, P. 1996. Etude de l’avifaune sur l’aire du projet de la ligne EDF Saint Pierre / Le Marigot en périodes de reproduction et de migrations pré et post nuptiales (mi-février à mi-octobre 1996). PNR/EDF, 157p.
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 we will post a final decision on this species’ Red List status on this page on 26 February 2024.
Recommended categorisation to be put forward to IUCN
Following further review, the recommended categorisation for this species has been changed following helpful comments made by P. Feldmann that indicate the extinction risk of this species was overestimated by the proposal to list as Endangered. With density data that had been overlooked, the species’ global population size (probably greatly) exceeds 10,000 mature individuals, and therefore does not meet or approach the thresholds for listing as threatened under Criterion C or D(1). Because this species has demonstrated resistance and fast recovery to previous strong hurricanes, it is now considered that the number of Locations is probably >>10, even though the species is confined to only two islands. Threats are also not thought to be operating at an acuity and scale from which a continuing decline in AOO, EOO or mature individuals can be inferred. However, a decline in habitat extent and quality is precautionarily inferred given the threat of hurricanes and potentially climate change related altitudinal shifts in habitat. Accordingly, the species qualifies as only Near Threatened under Criterion B. The data in the original proposal for Criterion A is broadly accepted, although the rate of past decline is changed to 10-29% to reflect uncertainty over recovery time. Blue-headed Hummingbird is now recommended to be listed as Near Threatened, approaching the thresholds for listing as threatened under A2c+4c;B1b(iii).
Many thanks for everyone who contributed to the 2024.1 GTB Forum process. The final 2024 Red List categories will now be published on the BirdLife and IUCN websites in October 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.