Editing Serengeti (section)

==Great migration==
[[File:Wildebeest-during-Great-Migration.JPG|thumb|upright=1.2|Migrating wildebeest.]]

Since the 1970s, each year around the same time, the circular great [[blue wildebeest|wildebeest]] migration begins in the [[Ngorongoro Conservation Area]] of the southern Serengeti in Tanzania and loops clockwise through the Serengeti National Park and north towards the [[Masai Mara]] reserve in Kenya.<ref name="The Great Wildebeest Migration">{{cite journal |title= The Great Wildebeest Migration: Exploring Africa's biggest wildlife phenomenon |year= 2017 |url= https://horizonguides.com/guides/great-wildebeest-migration-021}}</ref> This migration is naturally caused by the availability of grazing. The initial phase lasts from about January to March, when the calving season begins – a time when there is plenty of rain-ripened grass available for the 260,000 [[zebra]]s that precede 1.7 million [[wildebeest]] and the following hundreds of thousands of other plains game, including around 470,000 [[gazelle]]s.<ref name=aboutAfrica/><ref name=ngorongoro>{{cite web |url=http://www.ngorongorotanzania.com/get-there.html |title=How to Get There, Ngorongoro Crater |publisher=Ngorongoro Crater Tanzania |year=2013 |access-date=3 June 2014}}</ref><ref name=UNESCO>{{cite web |url=https://whc.unesco.org/en/list/39 |title=Ngorongoro Conservation Area |publisher=United Nations Educational, Scientific and Cultural Organization – World Heritage Centre |access-date=3 June 2014}}</ref>

[[File:Wildebeest crossing river - Stefan Swanepoel.jpg|thumb|left|upright=1.2|Wildebeest crossing the river during the Serengeti migration.]]
During February, the wildebeest are on the short grass plains of the southeast part of the ecosystem, grazing and giving birth to approximately 500,000 calves in 2 to 3 weeks. Few calves are born ahead of time and of these, hardly any survive, largely because very young calves are more noticeable to predators when mixed with older calves from the previous year. As the rains end in May, the animals start moving northwest into the areas around the [[Grumeti Game Reserve |Grumeti River]], where they typically remain until late June. The crossings of the Grumeti and [[Mara River |Mara]] rivers beginning in July are a popular safari attraction because crocodiles are lying in wait.<ref name=aboutAfrica>{{cite web |url=http://goafrica.about.com/od/africasafariguide/a/annualmigration.htm |title=The Great Annual Wildlife Migration – The Great Migration of Wildebeest and Zebra |publisher=About.com |author=Anouk Zijlma |access-date=3 June 2014 |archive-date=28 March 2017 |archive-url=https://web.archive.org/web/20170328053651/http://goafrica.about.com/od/africasafariguide/a/annualmigration.htm |url-status=dead}}</ref> The herds arrive in Kenya in late July / August, where they stay for the rest of the dry season, except that the [[Thomson's gazelle |Thomson's]] and [[Grant's gazelle]]s move only east/west. In early November, with the start of the short rains, the migration starts moving south again, to the short grass plains of the southeast, usually arriving in December in plenty of time for calving in February.<ref name=Croze>{{cite book |title=Serengeti's Great Migration |author1=Croze, Harvey |author2=Mari, Carlo |author3=Estes, Richard D. |publisher=Abbeville Press |year=2000 |isbn=978-0-789-20669-5}}</ref>

About 250,000 wildebeest die during the journey from Tanzania to the [[Maasai Mara]] National Reserve in southwestern Kenya, of {{convert|800|km|mi}}. Death is usually from thirst, hunger, exhaustion, or predation, including by [[big cats]].<ref name="partridge">{{cite news |first=Frank |last=Partridge |title=The fast show |date=20 May 2006 |url=http://www.findarticles.com/p/articles/mi_qn4158/is_20060520/ai_n16416123 |archive-url=https://web.archive.org/web/20071219104115/http://findarticles.com/p/articles/mi_qn4158/is_20060520/ai_n16416123 |url-status=dead |archive-date=19 December 2007 |work=The Independent (London) |access-date=14 March 2007}}</ref>