Justification of Red List category
The species is suspected of having undergone a moderately rapid decline across its range, with evidence of reductions in the south Asian and east Mediterranean populations (where the species has become extinct as a breeding species in Georgia and Türkiye), suspected declines in the largest south west Asian population centred on the Mesopotamian marshes, while the north African population appears to be stable. Overall the rate of reduction is suspected to approach the threatened thresholds, and Marbled Teal is assessed as Near Threatened.
Drivers of the decline are thought to be habitat destruction through wetland loss, degradation and disturbance as well as climate change, which amplifies the impacts of wetland loss and degradation through extreme weather events. Direct mortality from hunting is also thought to contribute to declines in parts of the range. Mitigation action does not appear to be sufficient to adequately address these threats and the long-standing declines in the population of this species are therefore suspected to continue.
There are estimates of the species four flyway populations as follows: west Mediterranean and west Africa 6,000-7,500 individuals, Eastern Mediterranean 20-100 individuals, south-west Asia 46,000-50,000 individuals, and South Asia c. 5,000 individuals (Wetlands International 2022). However, a number of these have no recent information and to incorporate uncertainty larger bounds are used here. For example, data for the south Asian wintering population dates from between 1987-1991: there are no recent records of large numbers from the area comparable with this number in the past decade. Updated values used are: west Mediterranean and west Africa 7,500-10,000 individuals, east Mediterranean 150-250 individuals, south-west Asia 7,000-50,000, and south Asia 350-1,000 individuals.
For the west Mediterranean and west Africa population count totals in winter have reached 7,435 individuals in 2017 (Nagy and Langendoen 2020), implying that the true number is somewhat higher than this given the large area of unsurveyed habitat across north Africa. The population size range is expanded here to 7,500-10,000 individuals, but it is noted there is the potential for it to be considerably higher.
There is considerable uncertainty in the size and trends of the south west Asia population, which is largely concentrated in the Mesopotamian marshes of Iran and Iraq. In 2010 winter counts over southern Iraq observed c. 44,000 individuals, possibly due to birds concentrating at single sites as a result of changes in water levels elsewhere in its range (Salim 2010). Subsequent changes to water availability across the region means that deriving national population estimates is difficult, and the significance of recent, much lower counts is uncertain. Fewer than 100 individuals were found between 2015-2016 surveys of Hor Al-Dalmaj and a maximum of 110 individuals were observed at Sawa Lake (Abed et al. 2017). Across the larger area between 2014 and 2018, 4,373 individuals were recorded (based on the highest annual IWC count; Wetlands International 2022), but there has been a subsequent single site count of 5,000 individuals during August-September 2021 in Hur al-Azim, Iran (which is connected to the wetlands of southern Iraq) (K. Hafezi in litt. 2022). The partially nomadic behaviour of the species makes it difficult to assess to what extent this reflects redistribution of birds particularly due to natural fluctuations in its population numbers every year (F. Botella in litt. 2022). Accounting for those in countries further north, the minimum bound for the south west Asian population is likely to be between 7,000 and 50,000 individuals.
The east Mediterranean population includes countries where rapid declines and extinctions have been documented: Georgia (where the last individuals were observed 'several decades ago': N. Paposhvili in litt. 2022) and Türkiye, where c. 120 breeding pairs at the start of the 1990s had dwindled to none by 2014 (Boyla et al. 2019, Ö.Ü. Özkoç in litt. 2022). However, larger numbers than recorded in recent census counts have been reported in Israel (e.g. Meyrav 2022), and the numbers breeding in Syria are unknown, such that there may have been a concentration of this population in the middle of this range. The range of 20-100 individuals for this region (Wetlands International 2022) may be too low, with around 200 recorded near simultaneously in Israel in June 2022 (eBird 2022), but these appear to represent the bulk of the remaining birds hence this population is thought to fall between 150-250 individuals.
There are few recent records of wintering birds in south Asia, though there is little coverage in Pakistan where most would be expected to occur (Green 1993). Hardly any have been reported via eBird in the past few years, which has very high numbers of active users in India (eBird 2022): the species appears to now be a rare visitor. Consequently it would seem unlikely that there are still 5,000 individuals regularly wintering in this this region, although it is suspected that many of these individuals have shifted their wintering areas or the extent to which they migrate rather than being entirely lost to the global population. Numbers wintering here and separate to those within the south-west Asian population are therefore placed in a band of 1,000-5,000 individuals.
Accordingly, the overall population is here estimated to fall between 15,000-61,250 individuals, rounded to 15,000-61,000 individuals, roughly converted to 10,000-40,000 mature individuals.
The overall population is suspected to be undergoing a moderately rapid decline.
In the south west Asian population there is evidence to suspect there has been a moderately rapid to rapid population decline, although recent short-term increases have been recorded in Iran and Iraq (Nagy and Langendoen 2020, Wetlands International 2022). The Mesopotamian marshes of Iran and Iraq are thought to have held up to c. 80% of the global population in the recent past, with very large counts of c. 44,000 individuals in winter 2010 appear to have been due to the concentration of individuals from across a large area due to widespread drought coinciding with the restoration of the Mesopotamian marshes (Salim 2010). Inevitably, subsequent counts have been smaller as environmental circumstances have altered, with the largest recent single-site count of 5,000 in August-September 2021 in Hur al-Azim, Iran (K. Hafezi in litt. 2022). It is suspected that there has been both a significant dispersal across the region of the birds counted in 2010, but also that this population has declined, potentially at a rapid rate, due to the continued impacts of habitat destruction through wetland disturbance and drainage, climate change and hunting, with added affects of invasive species and pollutants (K. Ararat in litt. 2022, S. A. Abed in litt. 2022, K. Hafezi in litt. 2022, S. Nagy in litt. 2022, M. A. Salim in litt. 2022, M. Shobrak in litt. 2022). Elsewhere, the trend is reported as stable in Azerbaijan, declining in Uzbekistan and Turkmenistan and unknown in Kazakhstan (Wetlands International 2022). Only small numbers remain in Armenia (Keller et al. 2020) where it is declining (Wetlands International 2022). It has been extinct as a breeding bird in Georgia for several decades (N. Paposhvili in litt. 2022).
The western Mediterranean and west African population has undergone several increases and periods of stability (Nagy and Langendoen 2020), although some of the apparent fluctuation may be due to variation in monitoring efforts (N. Petkov in litt. 2022). The reported trend for north African countries is uncertain, but counts indicate that it may have increased taking into account redistribution of individuals between countries (Wetlands International 2022). In Morocco, there is a stable long-term trend with winter counts averaging around 2,000 individuals for 2001-2005, 2006-2010 and 2011-2015; El Agbani et al. 2017, Qninba et al. 2017, Ouassou et al. 2017, M. Amezian in litt. 2022)). In other north African countries the trend is uncertain, with redistribution noted between Tunisia and Algeria (Wetlands International 2022), but there does not seem to be any evidence of significant abundance change. It is difficult to interpret the situation in Iberia, as reintroduction programmes distort population size estimates (see BirdGuides 2022, A. Green in litt. 2022, N. Petkov in litt. 2022): potentially 95% of the breeding population consists of individuals released from captivity (F. Botella in litt. 2022). It is suspected the species would be faring very poorly in the absence of releases given evidence of habitat deterioration across key sites in Spain (such as in Doñana and El Hondo; W. Duckworth in litt. 2022, A. Green in litt. 2022, N. Petkov in litt. 2022, T. K. Roy in litt. 2022) and possible hunting impacts (F. Botella in litt. 2022). The European population is now only a very small proportion of the global population.
The east Mediterranean population appears to be suffering ongoing and potentially rapid declines (Wetlands International 2022), including in Turkey a decline from c. 120 pairs in the early 1990s to extinction by 2014 (Boyla et al. 2019, Ö.Ü. Özkoç in litt. 2022). Only small numbers were reported as part of monitoring in Israel (Wetlands International 2022), however there are much larger recent counts from the country at additional sites (e.g. Meyrav 2022), suggesting that the true population there is larger.
Its status across South Asia remains uncertain (partly due to difficulty in interpreting clear population trends due to changing water levels and its nomadic behaviour), but it seems to now be much scarcer in India since the population was estimated at c. 5,000 in the early 1990s (Perennou et al. 1994, T. Mundkur in litt. 2021, T. K. Roy in litt. 2022). What is not clear is whether this reflects a shift in distribution, extent of migratory behaviour or a significant population decline. Similarly large counts of wintering birds in the 1990s in Pakistan (Green 1993) have not been reported recently and the area of suitable habitat is assessed to have shrunk (Chaudhry et al. 2019). While a redistribution may have occurred to some extent, it is sensible to assume a moderate to rapid decline here also.
Reflecting the uncertainty about the species' status across its range, but also that declines are affecting significant parts of the range, it is suspected overall the population is declining at a moderately rapid rate, placed in a band of 20-29% reduction over three generations (12 years), with similar rates projected in the future due to ongoing threats.
This species has a fragmented distribution in the western Mediterranean (Spain, Morocco, Algeria, Libya, Tunisia, Italy (Sicily and Sardinia) wintering in north and Sub-Saharan west Africa), the eastern Mediterranean (Türkiye [although possibly now extinct as a breeding species: Boyla et al. 2019, Keller et al. 2020], Israel, Jordan, Syria, wintering south to Egypt) and western and southern Asia (Azerbaijan, Armenia, Russia [where it is on the verge of extinction, Van Impe 2013], Turkmenistan, Uzbekistan, Tajikistan, Kazakhstan, Iraq, Iran, Afghanistan, Pakistan, India and extreme northwest China, wintering in Iran, Pakistan and north-west India) (Green 1996). The degree of separation of these subpopulations is uncertain, and there appear clear linkages between the south-west Asian and east Mediterranean populations. Breeding has formerly been recorded in Senegal and potentially the species may have bred in Chad (Green 1993).
The western Mediterranean population is concentrated in North Africa, with an estimated 47% of the population in Morocco based on 2019 data (Ouassou et al. 2021), while the population in Spain has fluctuated but is currently severely reduced, resulting in efforts to counteract declines through releases of captive-reared birds (BirdGuides 2022). It is unclear how many birds currently breeding in Spain are from releases, but more than 95% of the recorded 2021 breeding pairs were apparently captive-reared and released individuals (F. Botelli in litt. 2022) after 860 birds were released in 2021 (BirdGuides 2022). The population in Italy is very small and has not increased, also leading to conservation efforts involving the release of captive-reared birds in Sicily (Keller et al. 2020, A. Andreotti in litt. 2022). The breeding population in Türkiye is considered likely extinct with the last confirmed breeding before 2014 (Boyla et al. 2019, Keller et al. 2020). Formerly, the species bred on the Canary Islands (Cramp and Simmons 1977). It is also extinct in Georgia, where none have been seen for several decades (N. Paposhvili in litt. 2022).
Very large numbers were recorded following the restoration of the marshes of southern Iraq after 2002, particularly in 2010 when the surrounding region was particularly adversely affected by drought: this probably represented the concentration in this area of most of the south-west Asia non-breeding population. Since then numbers counted have been only a tenth of the peak in 2010 (Wetlands International 2022). The status and trend of the south Asia population are uncertain, with the most recent Waterbird Population Estimates data now 30 years old (Wetlands International 2022). There seem few recent records further east than India: the status of the breeding population in northwest China is uncertain.
The species makes dispersive and nomadic movements in relation to water levels over much of the range: in the east of the range movements are considered more predictable, but it is availability of shallow wetlands in arid areas that principally determines the movements of the species making it a challenging species to monitor.
Behaviour This species is dispersive and partially migratory (del Hoyo et al. 1992). It shows variable, nomadic movements and is capable of dispersal in search of suitable habitat at any time of year as changing conditions require (del Hoyo et al. 1992, Scott and Rose 1996, Kear 2005). There is a general tendency for a more southerly distribution during the non-breeding season and a more northerly distribution during the breeding season. It is highly gregarious post-breeding and during the non-breeding season when it occurs in large monospecific flocks of up to 2,000 individuals, and potentially >5,000 individuals (del Hoyo et al. 1992, Green et al. 2002, Kear 2005, A. Green in litt. 2016). During the breeding season it is more dispersive, although paired birds often mix with conspecifics (Kear 2005). Nests are sometimes built in close proximity to one another, although they become increasingly spaced out as population density declines (Kear 2005, Green 2007). Nesting has been recorded from mid-April to late June, and broods from mid-April to mid-September, this species being a later breeder than coexisting duck species (Green et al. 1999, Kear 2005). The species exhibits drastic population fluctuations, partly in response to annual variations in rainfall.
Habitat Breeding It is adapted to temporary, unpredictable, Mediterranean-type wetlands (Green 2000, 2007) and breeds in fairly dry, steppe-like areas on shallow freshwater, brackish or alkaline ponds with well vegetated shorelines, and rich emergent and submergent vegetation (Green 1993, Kear 2005, Sebastián-González et al. 2013). It also breeds on delta marshes where receding waters leave behind large areas of shallow water with abundant sedges and bulrushes (Johnsgard 1978). In addition it may use slow rivers and saline coastal lagoons, and man-made wetlands including fish-rearing ponds, small reservoirs and sewage farms (Green 1993, Y. Perlman in litt. 2013, Y. Artzi in litt. 2020). Although it favours brackish wetlands, it tends to avoid waters of high salinity. Microhabitat requirements are strongly influenced by diet. Non-breeding It uses similar habitat during the non-breeding season, although may make more use of shallow, mixed zones of emergent and saltmarsh vegetation during the summer (Sebastián-González et al. 2013).
Diet The diet varies considerably between seasons and sites and additionally with age. Diptera are an important component of the diet, especially before and during the breeding season. Small seeds become increasingly important after the breeding season with faeces of post-breeding birds in Türkiye composed of 95% dry weight Scirpus seeds (Green and Selva 2000, Green and Sánchez 2003, Fuentes et al. 2004). Newly hatched chicks are highly dependent on emerging chironomids (Green 2000).
Breeding site Nests are usually constructed on the ground at the water's edge, beneath a covering of vegetation (Green 1993, Kear 2005). They may also occur above water in Typha stands and are reported to have been found in the roofs of reed huts (Hawkes 1970, Kear 2005). Mean clutch size was recorded in Spain to be 11.8 (Green 1998).
Over 50% of suitable habitat may have been destroyed during the 20th century. Wetland drainage for agriculture and dam construction occurs across its range, most significantly in Iraq, where the species is threatened by fluctuating water levels and local water shortages. Hydrological work, eutrophication and introduction of carp and other alien species has severely affected breeding sites in Tunisia, Türkiye, Morocco and Spain (A. Green in litt. 2020). Reed-cutting, reed-burning and grazing commonly reduce the amount of habitat for nesting. Pollution from agricultural, industrial and domestic sources is a threat at many sites. Human disturbance and urbanisation is also increasing within the species' range (M. Houhamdi in litt. 2022, K. K. Pierre in litt. 2022). A lack of habitat following hot, dry summer months probably results in high juvenile and adult mortality post-breeding (Green 2000, 2007). Lack of water availability for the El Hondo reservoirs in Alicante, high fish densities and illegal hunting have led to a major decline in eastern Spain since 1998 (Ballesteros et al. 2008, A. Green, in litt. 2020). The passage of individuals between Spain and the north of Africa has been obstructed by the degradation of several wetlands in the Maghreb region, leading to decreases in the arrival of birds in the Iberian Peninsula.
In Iraq, the species is also threatened by illegal hunting and persecution, exacerbated by it being the principal wildfowl target for hunters during the summer months (Salim 2010). Brochet et al. (2019) estimated that 5,000–15,000 individuals are illegally killed/taken per year in the Arabian Peninsula, Iran and Iraq; this is approximately 17% of the global population. Hunting has also been attributed to declines in Pakistan (Chaudhry et al. 2019). Also in Pakistan, extensive netting operations occur in winter to supply the subsistence on duck meat by locals (Chaudhry et al. 2019). When breeding, the species is vulnerable to shooting and egg collection.
Further mortality results from birds caught in fishing nets, lead poisoning, and disease (Mateo et al. 2001, Kear 2005, Svanberg et al. 2006). Increasing spring temperatures (and subsequent fires; K. Hafezi in litt. 2022) and decreasing winter precipitation can negatively impact this species whilst drought can cause further disruption to water levels (M. Amezian in litt. 2022).
Conservation Actions Underway
CMS Appendix I and II. EU Birds Directive Annex I. It is legally protected in Bulgaria, Israel, Morocco, Spain, Russia, Tunisia and Türkiye. Marbled Teal occupies 25 wetlands having national and/or international conservation statuses: 15 Ramsar sites, 20 SBEI, 16 IBAs, 3 are part of national parks, and 10 are part of permanent hunting reserves (Ouassou et al. 2021). Key Biodiversity Area (KBA) project surveys were conducted in Iraq by Nature Iraq during 2005-2010, finding c.44,000 individuals in 2010 and resulting in the proposal of several KBAs which hold wintering and breeding populations to be designated as protected areas (Salim 2010). Awareness-raising efforts were carried out in Iraq including the production of posters and hosting of conferences and meetings with hunters and hunting societies by Nature Iraq (Salim 2010). Conservation programmes have been carried out in Spain, with the releases of hundreds of captive-bred birds there since 2000 potentially inflating numbers, albeit habitat degradation continues (A. Green in litt. 2020). In Italy, reintroduction programmes also continue in Southeastern Sicily, aiming to increase the breeding and wintering populations (C. Cappuzzello in litt. 2022). Survey and research projects have been carried out in Morocco, Türkiye, and Azerbaijan. An updated European action plan was published in 2008 (Iñigo et al. 2008). In the following National Red Lists, it is considered Vulnerable in Morocco (Red Bird list of Breeding threatened species in Morocco; I. Cherkaoui in litt. 2014), Endangered in Italy (Gustin et al. 2019), Critically Endangered in Spain (SEO/BirdLife 2021), and Regionally Extinct in Georgia (Paposhvili et al. 2021). A National Action Plan is in development by the Iraqi Organisation for Conservation of Nature (IOCN) (S.A. Abed in litt. 2022).
39-42 cm. Small, grey-brown dabbling duck. Brownish body flecked with creamy-brown. Dark eye-patch and broad eye-stripe from eye to nape. No speculum. Elegant shape, slightly crested appearance and long neck and wings. Female slightly smaller. Characteristic low, slow flight. Similar spp. Northern Pintail Anas acuta female is larger, lacks eye-patch and has scalloped flanks. Red-crested Pochard Netta rufina female is larger, has more extensive eye-patch and strong contrast between flight feathers and forewing. Voice Squeaking jeep uttered by displaying males. Otherwise relatively silent.
Text account compilers
Martin, R., McGonigle, K., Fernando, E.
Abed, S., Amezian, M., Andreotti, A., Ararat, K., Artzi, Y., Ashpole, J, Bos, J.F., Botella, F., Capper, D., Cappuzzello, C., Cherkaoui, I., Derhé, M., Duckworth, W., Ekstrom, J., Gilissen, L.M., Green, A.J., Grice, H., Hafezi, K., Harding, M., Houhamdi, M., Hughes, B., Malpas, L., Mundkur, T., Nagy, S., Paposhvili, N., Peet, N., Perlman, Y., Petkov, N., Pierre, K., Piggott, A., Pilgrim, J., Roy, T., Rutherford, C.A., Salim, M., Shobrak, M., Staneva, A., Temple, H., Westrip, J.R.S. & Özkoç, Ö.
BirdLife International (2023) Species factsheet: Marmaronetta angustirostris. Downloaded from http://datazone.birdlife.org/species/factsheet/marbled-teal-marmaronetta-angustirostris on 04/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 04/10/2023.