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).

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.

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). 

Conservation Actions Proposed
Conduct regular surveys and monitoring. Research its ecology. Develop a national conservation and management plan in Pakistan (Chaudhry et al. 2019). Develop a management plan for the hydrological, ecological, and developmental preservation of Hor Al-Dalmaj, Iraq (Abed et al. 2014a).
Protect habitat at all sites regularly holding the species. Prevent eutrophication, fish introductions, mortality from hunting and other causes. Increase public awareness of the species and its habitat. The 'Dalmaj Protection Force' (local police) and 'Friends of Dalmaj' (local conservation group) could be targeted to raise awareness and assist in monitoring programmes in the future (Abed et al. 2014b).