Northern Bald Ibis

## About

A tagged northern bald ibis standing on a rocky outcrop.

The northern bald ibis ***(Geronticus eremita)*** or hermit ibis, is an extremely rare ibis species native to areas of northern Africa and southwest Asia. The bald ibis possesses glossy black plumage which appears green, violet, magenta and blue due to its iridescence. The black feathers camouflage the species at night, as a means of avoiding predation while sleeping. The feathers of the ibis' ruff are wispy and long in contrasts to the bird's un-feathered head, which gives the species its name. These wispy feathers help the ibis hide its head at night to avoid predators, as the head itself is a dull red or pink in colour which is easily spotted. The beak is long and downturned slightly, a characteristic of ibis species. Male bald ibises grow to 75-80cm (29.5-31.4in) in length while females are on average smaller in length at only 70-73cm (27.5-28.7in). Both sexes weigh around 0.8-1.4kg (1.76-3.08lbs).

## Diet

Northern bald ibises are carnivorous birds. They eat mostly insects, arachnids, worms and other invertebrates but are also known to prey on small mammals, ground-dwelling birds and reptiles like desert snakes and lizards. It is also thought that bald ibises may eat carrion. They hunt by probing their curved bills into loose sand or soil and feeling for prey. It is important that terrain of this consistency is abundant where bald ibises migrate and settle, as too much plant life can obstruct foraging efforts. Bald ibises may forage up to 15km (9.3mi) from their colony.

## Conservation Status

Northern bald ibises were classed as a critically endangered species by the IUCN up until very recently when they were revaluated to endangered in 2018, due to an increase in breeding populations. Factors which contribute to ongoing decline include; human-caused threats, predation, egg poaching and unidentified natural forces which collectively threaten specific subpopulations of bald ibis. In Ethiopia were ibis wintering grounds are located, threats to the species include; the conversion of habitat into cultivated farms and commercial use of pesticides is likely to threaten the bald ibis population in the long-term, while rainfall shortages are thought to be a short-term threat. In Morocco, disturbance to breeding areas has become common and carelessness may lead to detriment to the population, whilst in Türkiye, historical poisoning of the bald ibis has greatly decreased breeding success and proficiency. In Syria threats to the bald ibis are most well-documented however, current tensions in the region due to conflict has made it difficult to assess threats and discern whether the species is still extant in the nation at all. Regardless, habitat degradation in the form of firewood collection, overgrazing and livestock disturbances threaten the species, as well as food ability declining as a result. Similarly, oil concessions, infrastructural developments and potential urbanisation all posed a potential threat to the bald ibis through habitat destruction and possible habitat fragmentation however, these projects were cancelled following conflict escalation. The most contributing factor to bald ibis decline in the Arabian peninsula is hunting and trophy hunting, which has decimated the population in the region to the point where breeding productivity in Syria was zero in 2005. This issue is best illustrated through the tagging of three birds in the summer of 2010, none of which reached their first winter as a product of hunting. Nest predation is also fairly common, with young and eggs being taken by Egyptian vultures ***(Neophron percnopterus)*** and brown-necked ravens ***(Corvus ruficollis)***. Breeding losses to egg predation have occurred in Souss-Massa National Park, Morocco in particular, where this has been a prevailing issue, along with persistent starvation. The northern bald ibis also went extinct in Europe during the early to mid 1600s, where it was hunted prolifically. Fortunately however, the species has since been reintroduced to Europe, now once again inhabiting areas of the German, Austrian, Swiss and Italian alps, where it once existed in great numeracy. Reintroduction programs have been manned by the Waldrapp Project, A European based conservation and re-wilding organisation which aims to reintroduce the ibises to central Europe. From 2014-2019 the Waldrapp Project managed to release 142 captive-bred individuals into the wilds of Europe however, illegal hunting in Tuscany, Italy where the birds migrate, led to a substantial loss. From 2022-2028 the project has gained increased funding via the EU and related partners and co-financers, such as Zoo Vienna and the WWF. They hope to establish a sustainable breeding population of approximately 260 migrating individuals by 2028. In the four countries where the birds have been released, actions to eliminate poaching and electrocution via powerlines have been proposed, being raising awareness through campaigning for the bald ibis and regulation and re-securing of medium voltage pilons respectively.

## Range and Population

The northern bald ibis once inhabited the majority of north Africa, the Middle East and west Asia as well as much of central Europe however, today the species is limited to select regions. In Africa and Asia, they occur in arid environments like deserts, scrublands, steppes and cliffsides in particular however, the European population favours the cooler alps and mountains. The bald ibis is still frequently found in Africa, particularly in Morocco where the population is considered to be stable by the IUCN and consisted of 580 overall individuals in 2015, with 116 breeding pairs having been identified. These were the best breeding records to date since detailed records of the bald ibis population had begun being taken. There is also a chance that natural ibis repopulation of former African range is possible, as individuals have been found in areas where the species was thought to be extinct. The eastern (Middle Eastern) population of the bald ibis was long thought to have been wiped out by continual hunting however, a colony of just seven ibises was found to be living in Syria in 2002. As the eastern bald ibis population is migratory, the individuals and population is harder to monitor overall and it was correctly predicted that the population would eventually die out. Before the population likely disappeared in 2015 however, between the years of 2005-2007 the colony successfully fledged 24 chicks. Further colonies were unfortunately not found through a geographical survey of Syria in 2003. The Syrian population is known to have migrated to Ethiopia for the winter months however, the last sighting of an Ethiopian ibis was in 2015, further cementing the likely extinction of the population. A semi-wild population has however, been conserved in Birecik, Türkiye.

## Behaviour

The behavioural characteristics of the northern bald ibis differ between populations, particularly between the continental populations. Eastern ibises travel from Syria southward to Ethiopia for the winter breeding season, flying through Jordan, Saudi Arabia and Yemen to reach the grounds, before returning at the season's end through Eritrea, Sudan, Saudi Arabia and Jordan as late as November. The European populations have also began migrating, flying from the alps to Tuscany. Bald ibises live in colonies of multiple birds and will settle along rocky enclaves or cliffsides to breed. The Birecik population is conserved through human intervention and pairs are provided nest-boxes for breeding as opposed to natural cliffsides favoured by wild populations. In order to prevent migration and by extension possible loss of breeding pairs, this population is captivated during the breeding season. Breeding begins in February and eggs are laid in late April-early May. Once eggs hatch, the pair will alternate between foraging for the young and protecting the young until the chicks are fully fledged (2-4 years of age). Colonies may remain occupied until June and July however, most pairs migrate back to Syria in August. When courting, a male ibis will emit a deep coughing call known as a "croop" in an attempt to attract a female. Pairs are monogamous and will breed with each other exclusively. When situated in colonies, ibises will be loosely connected while foraging for food however, they will reunite when roosting, breeding or flying in a flock. Winter flocks vary in size from a few individuals to up to a hundred and generational hierarchy is frequent, with older birds leading the flock. Untagged birds were also discovered in Israel and Djibouti however, it is unknown whether they represent the Syrian population or an undescribed one. The African -or rather Moroccan- population is dispersal and fledged young have been found to travel the furthest from their original birth site however, this distance may be determined by the amount of collective rainfall that season brings. Breeding success is also likely tied to rainfall excess. It is suggested that the Moroccan population has no need to migrate due to coastal fogs which increase humidity and compensate for low rainfall, warranting year-round occupation of sites like Souss-Massa National Park.

### Relationship with Humans

The bald ibis has long been relevant in religious culture, having been noted as being among the first of the birds to be let off the ark by Noah as a sign of repopulation and fertility. This religious significance is what allowed the species to remain prevalent in Birecik, Türkiye, as it was regarded as holy in Islam. Many Birecik locals also celebrate the return of the bald ibises from their migration in the ancient 'Kelaynak yortusu' festival in mid-February. Kelaynak yortusu originally began as a way to honour the ibises for guiding the Hajis (pilgrims) to Mecca yearly through their migration. In ancient Egypt, the bald ibis was also incredibly influential, representing Thoth, the Egyptian scribe of the gods who is often depicted as a man with the head of an ibis. The ancient Egyptian "akh" meaning "to shine" or "resplendent" is represented by a bald ibis in hieroglyphic form. "Akh" also denotes excellence, glory and virtue in an abstract sense. Today, the rarity of the northern bald ibis brings tourism to the areas where it is still extant.

## In Captivity

The northern bald ibis is actually incredibly common in European, Japanese and North American zoos, with a total of around 1,000 birds in captivity in total. All captive individuals currently in zoos originate from the Moroccan population of bald ibis and every individual originates from one of three bloodlines originally extracted from the country. The first of the bloodlines was exported from Morocco to stock Zoo Basel, Switzerland in the 1950s-60s, the second bloodline was to stock Rabat Zoo, Morocco in the 1970s and the third was to stock Naturzoo Rheine, Germany in 1976-78. Every subsequent individual is a descendant of these original bloodlines. From 1976 to 1994 captive-bred individuals from Birecik Aviary, Tel Aviv Zoo, Israel and Almeria Zoo, Spain were released into the wild however, these attempts were fruitless. Today, the 49 European-based zoos which house the species breed a collective 80-100 birds per year and this captive population stability was the reasoning for the bald ibis' reclassification as an endangered species in 2018.

## Sources

* IUCN Red List of Threatened Species - https://www.iucnredlist.org/species/22697488
* Northern Bald Ibis | Wikipedia - https://en.wikipedia.org/wiki/Northern\_bald\_ibis
* Northern Bald Ibis: baldly leading the way in ibis conservation | Birdlife International - https://www.birdlife.org/news/2019/05/29/northern-bald-ibis-baldly-leading-the-way-in-ibis-conservation/
* Northern Bald Ibis | Animal Diversity Web, University of Michigan Museum of Zoology - https://animaldiversity.org/accounts/Geronticus\_eremita/
* After a 400 Year Absence, a rare Ibis Returns to European Skies | Yale Environment 360 - https://e360.yale.edu/features/after-a-400-year-absence-waldrapp-rare-ibis-returns-to-european-skies
* Home | Waldrapp Project - https://www.waldrapp.eu/project-info/