VU
African Houbara Chlamydotis undulata



Justification

Justification of Red List category
This species is suspected to be in rapid continuing decline and to have declined very rapidly in the past decade, owing mainly to hunting pressure and ongoing habitat loss and degradation. Although a captive breeding and release programme is ongoing in Morocco, evidence that these releases are mitigating the rate of the decline in the wild population is not apparent, nor is there evidence that these ongoing releases have resulted in an additional sustainable subpopulation. To the contrary, monitoring of the area that has received the most released birds over the longest period concludes that the population in a 50,000 km2 area of eastern Morocco is not viable without ongoing releases, and must now be excluded from this assessment as a managed subpopulation. The loss of a population estimated to be around 3,400 individuals in 2001, at the start of the releases, is additional to a suspected rapid rate of ongoing reduction in the rest of the range, evidenced by range contraction and reduced densities. Hence the recent rate of population reduction is suspected to have been greater than the ongoing and future rates, and much improved monitoring to discern trends is needed. If further parts of the population are converted through releases to managed subpopulations then the recent rate of reduction will quickly increase and the species will qualify for a higher threat category. The causes of this reduction have not ceased.
Further research is needed to disentangle the impact of large-scale releases wherever these birds end up to determine the effect on the overall population demographics, and hence population viability. It has been stated that the large-scale releases prevented total extirpation from the monitored area in eastern Morocco: if that is true, logically wild populations may soon be extirpated from those areas not subject to such intensive conservation action. But equally, other areas that are subject to the level of intervention are expected to follow the same trajectory to becoming managed subpopulations requiring high inputs of captive-reared birds. Therefore the expansion of the conservation strategy to further areas must be subject to a careful evaluation of outcomes and full disclosure of projected population trajectory prior to the numbers of released birds exceeding the existing wild population. Precise data on known and projected mortality would be essential to informing the conservation in each 'block' of the population where large-scale releases to support the population are proposed: given the effort expended on conservation of this species it would seem a significant oversight if precise hunting take data are not available to assist with these assessments.
In conclusion, a rapid population reduction is continuing throughout the mainland range of African Houbara, which has been exacerbated to a degree by the change to a managed subpopulation of a small but significant proportion of the overall population. The species is accordingly assessed as Vulnerable. However, there is considerable uncertainty over the longer-term status of wild, unmanaged populations of African Houbara in mainland Africa. Were the conservation efforts that have been carried out in eastern Morocco applied across this range there is a considerable risk that the result would be the continued presence of the species, but not as a viable, wild population. Only the small population on the Canary Islands has not received individuals from releases of captive-reared individuals and requires continued protected and monitoring. There is an urgent need to assess the current wild occupancy, abundance and population trajectory across the historical range in light of this conclusion, and to fully assess the future impact of the release of captive-reared birds to prevent the loss of unmanaged wild populations. 

Population justification
In the mid-1990s this species' population was estimated to number 10,550 individuals (Goriup 1997). The population of nominate undulata in the mid-1990s was estimated to be at least 9,800 individuals, of which over 50% were in Algeria, 30% in Morocco and 10% in Libya (Goriup 1997). No overall estimate of the size of the wild population in North Africa has been made since due to the difficulty in adequately sampling across the range. Detailed population monitoring using point counts has been undertaken within the Emirates Center for Wildlife Propagation (ECWP) intervention area in eastern Morocco, which totals around 50,175 km2 (Hardouin et al. 2015, Monnier-Corbel et al. 2022). The first assessment of density returned values of 0.05 individuals per km2 in hunting areas and 0.1 individuals per km2 in protected areas, giving an estimate of around 3,400 individuals in the whole area (Hardouin et al. 2015, Dolman et al. 2021, Monnier-Corbel et al. 2022). If this value is used as a precautionary minimum for half the population size for Morocco (as the species occurs across much of the thorn-scrub desert in southern Morocco, a much larger area but likely at lower densities), then if the Moroccan total represents approximately 30% of the global population a minimum value for the latter would be around 22,600 individuals, more than double the value suggested by Goriup (1997).

Within the ECWP numbers of birds released increased annually (ECWP 2014, 
Hardouin et al. 2015, Monnier-Corbel et al. 2022) and this correlates with a rapid increase in the density recorded in surveys, up to 0.76 and 0.84 in 2010 (Hardouin et al. 2015, Monnier-Corbel et al. 2022), corresponding to a peak abundance estimated at 32,401 individuals (95% confidence limits 24,608-42,662) across the ECWP area (Monnier-Corbel et al. 2022). This population appears to have then severely declined in the following two years (although Monnier-Corbel et al. [2022] report no significant trend) with the estimated number of individuals in 2013 at 10,409 (8,667-12,500) (data from Monnier-Corbel et al. 2022). The total number released into this area actually exceeded the estimated population in both 2013 and 2014: subsequently (data to 2018) the population has been comparatively stable, ranging between 13,207-16,329 individuals but with 12,350 and 11,000 released in 2015 and 2016, and 7,050 and 6,700 released in 2017 and 2018 (data from Monnier-Corbel et al. 2022). Monnier-Corbel et al. (2022) conclude that the population within the ECWP does not currently meet criteria for viability and self-sufficiency, mirroring a conclusion published in a 2017 thesis (Bacon 2017) that the 'North African Houbara bustard population is not viable without reinforcement interventions in the long run'. Populations that are regularly supplemented from captive stock to prevent imminent extinction (i.e. within 10 years), as appears to apply within the ECWP area, are not considered in the determination of the species' Red List status except in consideration of species Extinct in the Wild (IUCN 2022). This situation has arisen only recently (Monnier-Corbel et al. 2022) and has had the effect of removing a significant part of the population from the scope of this assessment within the past three generations.

There is also evidence of a contraction in the range and reports of it becoming more difficult to find where it does still occur. It is now very rare in Western Sahara, having suffered a rapid decline in the 20th century (Bergier et al. 2017). In Tunisia it is now restricted to remote areas in the extreme south (Chammem et al. 2012) which suggests there are far fewer here than previously suspected (D. Jurek in litt. 2015) and there may only be a few hundred individuals in the country. Very little information is available from Libya, where there have been releases (e.g. 300 in 2010-11) (Dolman et al. 2021). There is a very large extent of potentially suitable habitat in Libya, but equally there is hunting and no information on impacts on either population size or demography. Given the sheer number of released individuals it is now very difficult to assess the wild population size in Morocco and adjacent areas of Algeria. The latter has received relatively few released individuals (although the number that may have dispersed into Algeria from Morocco is unknown and more releases are taking place) and possesses a very large extent of suitable habitat. There do not appear to be any data on hunting levels in Algeria but Berredjouh et al. (2016) noted hunting parties may last more than a month and take several hundred or even a few thousand individuals. The same study found the species was rare but a population remains in Ouled Djalel, Besbes and Ras Elmiaad regions in Biskra province in central Algeria (Berredjouh et al. 2016, Berredjouh 2021). There have never been accurate data from Mauritania, where some releases have taken place, but it is suspected that any population here is small and also subject to an unknown level of hunting.

Applying a three-generation reduction of between 30-50% as suspected to the tentative 2001 value of around 22,000 individuals results in a 2022 total between 10,450 and 14,975 individuals. This is an uncertain value given the lack of quantified data for the majority of the range, and may be a considerable underestimate. There is an urgent need for a rangewide assessment of the current wild population size, and establishing the existing population size is a pre-requisite for each area targeted for large-volume releases to allow evaluation of the impact of releases. While the ECWP release area may no longer be considered part of the wild population for this assessment, there are no barriers to the dispersal of released birds into surrounding, unmonitored areas and many further releases have been made in other locations, notably in Algeria but also in Mauritania and Libya (Dolman et al. 2021). No data on the pre-release population in these areas appears to be available and there does not appear to be any ongoing monitoring equivalent to that within the ECWP. While a tentative wild number of individuals is presented here, largely in order to consider plausible population reduction scenarios to inform this assessment of extinction risk, the true number currently living in North Africa (wild, released and offspring of released birds) and how that relates to the wild population size is highly uncertain. 

The Canary Islands subspecies C. u. fuertaventurae, is confined to the eastern Canary Islands with a population estimated at 537-577 individuals (Ucero et al. 2021). Most are now on Lanzarote, where the population was almost extirpated due to persecution in the 20th century (Horreo et al. 2023) but since hunting was banned in 1971 the population has increased (Schuster et al. 2012, Horreo et al. 2023) to 440-452 adult individuals in 2018 (Alonso et al. 2020), with 460 reported in 2020 (de Colsa et al. 2022). A total of 85-109 are present on Fuerteventura (Ucero et al. 2021), although 160 individuals were estimated 2020 (de Colsa et al. 2022). Not much more than a handful remain on La Graciosa with 12-16 estimated by Ucero et al. (2021). Previous estimates are difficult to compare, with changes to methodologies used and discrepancies in coverage confounding efforts to census what is a difficult species to monitor. In the mid-1990s it was estimated at 527 birds, with 241 on Fuerteventura, 268 on Lanzarote and 18 on La Graciosa (Martin et al. 1997) while two studies in the early 2000s placed the population around a thousand birds: Carrascal et al. (2006, 2008) estimated 108-252 birds on Fuerteventura, 272-801 on Lanzarote and 3-10 on La Graciosa whilst Lorenzo et al. (2007) estimated the population at c.1,000 birds across all the islands.
Bearing in mind the caveats given above, the overall global population is suspected to fall between 11,000-30,000 individuals.

Trend justification
The species showed a steady decline of c. 25% in the 20 years preceding 2004 (F. Launay pers. comm. 2004). Subsequently reports are of it becoming more difficult to find (D. Jurek in litt. 2015) and the severity of threats including hunting pressure and habitat loss and degradation was considered likely to be causing rapid declines (Chammem et al. 2012, Banos-González et al. 2016, Bacon et al. 2019), suspected to exceed 30% over a three generation period (BirdLife International 2016). This rate had the potential to slow as a result of a captive breeding and release programme in eastern Morocco and western Algeria (Lacroix et al. 2003, O. Combreau in litt. 2012), but the very large numbers of individuals released coupled with hunting have resulted in this population being assessed as no longer a viable self-sustaining population (Bacon 2017, Monnier-Corbel et al. 2022). In 2001, before the intensification of releases, this population was estimated at 3,400 individuals (Hardouin et al. 2015) suggesting a rough minimum global population size around 22,600 individuals (see notes under Population Size).

Assuming population reductions have proceeded at between 30-50% over three generations since 2010, bounds of the population size in 2022 would fall between 10,500-15,400 individuals (exponential model of reduction), or 10,600-15,470 individuals (linear reduction). The managed subpopulation within the ECWP requires subtracting from this value, but must also have this assumed rate of decline applied to be an appropriate counterfactual, hence would be between 1,640 (50% reduction) and 2,325 (30% reduction) individuals in 2022. Subtracting this from the global total gives a mean rate of reduction over the past three generations of 40% (40-57%) (where the maximum rate is based on a linear model of reduction). It is noted that the causes of the removal of the ECWP population are reversible and understood, however the driver of the reduction either overall or for this population has not ceased.

Given that the rate of reduction was suspected to have exceeded 30% over three generations only recently, the best value is still considered to be within the lower half of the range. Therefore, with the additional removal of the managed subpopulation, the rate of reduction is suspected to have fallen between 40 and 50% over the past three generations, and also to fall in this range over the three generations beginning 2013, the year where the ECWP population was excluded on the basis that this was the first year that releases exceeded the estimated population size.

Future rates of reduction will be dependent upon the maintenance of the remaining mainland population as unmanaged and wild. One additional area becoming a managed subpopulation within the current three-generation period would tip these tentative calculations into indicating a rate of reduction in excess of 50%, and employing large-volume releases of captive-reared birds across the whole mainland range risks all individuals being classed as managed subpopulations. 

The Canary Islands population is now thought to be stable or declining slowly (de Colsa et al. 2022, Ucero et al. 2021), though trends have been hard to recover from monitoring (Geary et al. 2022) and reports to the European Commission indicated an increasing trend until recently (BirdLife International 2021). On Lanzarote the species was almost extirpated by the mid-20th century with only 20 birds estimated in 1979 (Lack 1983) but has recovered notably since to around 450 individuals (de Colsa et al. 2022, Ucero et al. 2021, Horreo et al. 2023). It is uncertain whether this population will continue to grow, while on Fuerteventura a slow long-term decline (Carrascal et al. 2008, Horreo et al. 2023) appears to be driven by habitat degradation due to aridity and abandonment of traditional agriculture, which are suspected to be causing observed poor breeding success (Horreo et al. 2023).

Distribution and population

This species occurs across a wide range in North Africa. The nominate subspecies occurs in northernmost Mauritania, Western Sahara, Morocco, Algeria, Tunisia, Libya and Egypt west of the Nile, with old records from Sudan, although the current status there is uncertain and it may be extinct (more recent records may pertain to C. macqueeni). However, it has been reported that it is becoming more difficult to find the species in Tunisia, it may be close to extinction in Egypt and it may now occur only in disconnected areas in Algeria, which suggests the distribution may be smaller than previously documented (D. Jurek in litt. 2015). In Tunisia, the species was historically widely distributed, but only small relict populations remain in the most remote southern areas (Chammem et al. 2012). Subspecies fuertaventurae is confined to the eastern Canary Islands, Spain, with most in Fuerteventura and Lanzarote plus a very small number on the small islet of La Graciosa.

Ecology

The species inhabits sandy and stony semi-desert and is specialised to arid conditions where trees are absent and both shrub cover and herb layer are sparse (Collar 1979, Goriup 1997, Snow and Perrins 1998, Martí and del Moral 2003), and appears to prefer remote areas away from human settlement (Chammem et al. 2012). It feeds on invertebrates, small vertebrates and green shoots, with a generalist and opportunistic diet (Bacon et al. 2019). North African populations may be sedentary or partially migratory, moving relatively short distances to find recent plant growth (Snow and Perrins 1998).  
Males attract their mates with an extravagant courtship display which they perform at the same site each year. The display begins with a period of strutting and culminates with the male retracting his head within an ornamental shield of erected neck feathers and then running at speed in either a straight or curved line. The display is often accompanied by a series of subsonic booming calls (Gaucher et al. 1996). In eastern Morocco, females breed from mid-February to mid-June, and then will generally lay two to three eggs on the ground (Bacon et al. 2019). Therefore, eggs and young are susceptible to ground predators.

Threats

There is an ongoing threat of intensive hunting, which has worsened with the increased use of firearms, off-road vehicles and other technology, with 2,000 birds harvested every year from eastern Morocco since 2014 (Azafzaf et al. 2005, Michler 2009, Bacon et al. 2019). Although a captive breeding and release programme has been established with the intent to ensure that hunting is sustainable (Lacroix et al. 2003, Lesobre et al. 2009, Dolman et al. 2021, Monnier-Corbel et al. 2021), there is no clear evidence that this is supporting wild populations, with 80% of hunted birds in Morocco being captive-bred individuals (Bacon et al. 2019) and the population within the release area no longer viable without ongoing releases of cative-reared birds (Monnier-Corbel et al. 2022). This situation may be partly due to the lower breeding performance of captive-bred released females relative to wild-born females (Bacon et al. 2019), but it seems likely that mortality rates throughout the release site remain too high. Away from Morocco hunting groups have been recorded in Algeria (Berredjouh et al. 2016) and is also though to occur in Libya and Mauritania, but there has been no systematic assessment of hunting take across the range.

The primary threat from hunting is compounded by pressures on the species' habitats, from agricultural expansion, over-grazing of livestock, road construction, other infrastructure development and tourism developments (Azafzaf et al. 2005). There is conflict with urbanisation and agricultural development, as the species favours flat and vegetated plains (Carrascal et al. 2008). In Tunisia, a growing human presence and land transformation is rapidly leading to the loss of the small remaining populations here (Chammem et al. 2012). Eggs are also susceptible to trampling by livestock and collection by humans. Disturbance can be caused by oil exploration activities, along with disturbance associated with other threats. Locust control programmes can lead to direct and indirect poisoning of birds and a reduction in food supply. Floods and droughts cause additional pressures (Azafzaf et al. 2005).

Subspecies fuertaventurae is threatened by collisions with powerlines (C. González and J.A. Lorenzo in litt. 2007, Lowen 2007), as well as habitat degradation caused by tourist facilities, off-road vehicles, military exercises, overgrazing, sand extraction and road development, and possibly also nest predation by introduced mammals and illegal hunting (Martín et al. 1997, Martín and Lorenzo 2001, Martí and del Moral 2003). Recent evidence suggests that the impact of military exercises and hunting have reduced considerably on these islands in recent years, but mortality from powerlines may still be significant (C. González and J.A. Lorenzo in litt. 2007, Carrascal et al. 2008). In Fuerteventura, primary habitat loss of around 13.3% from 1996-2011 was estimated, with a consistent decrease in the species' population of 29% (Banos-González et al. 2016).

Conservation actions

Conservation Actions Underway
CITES Appendix I. EU Birds Directive Annex I. Bern Convention Appendix II. National legislation protects the species or controls hunting in most range states; however, hunters are often able to circumvent these laws (Azafzaf et al. 2005). 
The nominate subspecies in North Africa was the subject of an action plan (Azafzaf et al. 2005). A captive breeding and release programme aimed at population reinforcement is on-going (Lesobre et al. 2009, Dolman et al. 2021, Monnier-Corbel et al. 2022). The Emirates Centre for Wildlife Propagation (ECWP) was created in 1995 and manages African Houbara populations within a 50,170 kmintervention area in eastern Morocco, containing protected areas and hunting areas (Monnier-Corbel et al. 2022). There are now captive breeding centres in both Morocco and Algeria, with the majority of birds produced by the International Fund for Houbara Conservation (IFHC) at the ECWP at Missour and Enjil in eastern Morocco (IFHC 2013, Dolman et al. 2021). In the ECWP area a total of 108,915 individuals were released between 1998-2019 with 90% after 2009 (Monnier-Corbel et al. 2022), with c. 135,000 released over this period in the whole of Morocco (Monnier-Corbel et al. 2021). Releases have also taken place in Mauritania (2,200 in 2017-18), Algeria (9,921 between 2011-2019) and Libya (300 in 2010-11) (Dolman et al. 2021). However, despite the very high level of releases the ECWP population does not meet criteria for viability and self-sufficiency (Bacon 2017, Monnier-Corbel et al. 2022). The conclusion is that a population of c. 3,400 individuals in 2001 is now sustained only by continued releases of reared individuals. The programme has preserved the genetic diversity of the species (Lesobre et al. 2010, Rabier et al. 2020). However it may have introduced traits of domestication into the released birds changing or compromising the demography of the population (Dolman et al. 2021).
Subspecies fuertaventurae has received improved protection from poaching, reduction of grazing (agricultural decline) and habitat management within protected areas (Martín et al. 1997, Martín and Lorenzo 2001, Martí and del Moral 2003). SEO/BirdLife purchased a 209-ha reserve to protect the species on Fuerteventura in 2005. Earlier, the introduction of a hunting ban in 1971 on Lanzarote appears to have been instrumental in preventing extinction there: genetic data indicate a severe 20th century bottleneck consistent with reports at the time of the very small population, which has subsequently recovered (Horreo et al. 2023). 

Conservation Actions Proposed
Carry out comprehensive and coordinated surveys to establish the total population size and quantify the overall trend, as well as to clarify the current distribution. Establish robust, workable systems for the sustainability of hunting throughout range. Create hunting preserves and other types of managed protected areas. Reduce grazing and other farming pressures (Goriup 1997, O. Combreau and M. Lawrence in litt. 2004, F. Launay pers. comm. 2004). Study the impacts of releasing captive-reared birds on the demographics and genetic structure of the whole population.
For subspecies fuertaventurae: designate new and expand existing special protected areas under European law. Increase wardening of key areas. Ensure safe powerline positions; conduct a rigorous census every five years. Undertake local awareness campaigns (Martín et al. 1997, Martín and Lorenzo 2001, Martí and del Moral 2003).

Acknowledgements

Text account compilers
Martin, R.

Contributors
Allinson, T, Ashpole, J, Ayé, R., Burfield, I., Butchart, S., Collar, N., Combreau, O., Derhé, M., Gilroy, J., González, C,, Grice, H., Hingrat, Y., Islam, Z., Iñigo, A., Khwaja, N., Launay, F., Lewis, A., Lorenzo, J.A., Piggott, A., Pople, R., Rutherford, C.A., Staneva, A., Symes, A., Taylor, J., Westrip, J.R.S., Rotton, H. & Kessler, M.


Recommended citation
BirdLife International (2024) Species factsheet: Chlamydotis undulata. Downloaded from https://datazone.birdlife.org/species/factsheet/african-houbara-chlamydotis-undulata on 21/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 21/02/2024.