{
 "title": "Masai Mara migration seasons 2001 to 2026",
 "description": "The wildebeest migration in the Masai Mara, Kenya, season by season from 2001 to 2026: first groups, first large herds, first Mara River crossing, departure, and the herds month by month from June to December, from the Mara Conservancy's monthly reports (Mara Triangle).",
 "licence": {
  "id": "CC-BY-4.0",
  "name": "Creative Commons Attribution 4.0 International",
  "url": "https://creativecommons.org/licenses/by/4.0/"
 },
 "attribution": "masaimara.info, Masai Mara migration seasons 2001 to 2026, CC BY 4.0, https://masaimara.info/data/",
 "page": "https://masaimara.info/data/",
 "built": "2026-11-13",
 "temporalCoverage": "2001/2026",
 "spatialCoverage": "Masai Mara, Kenya",
 "sources": [
  {
   "body": "Mara Conservancy",
   "document": "Mara Monthly, the monthly reports of the Mara Triangle, one web page per month",
   "url": "https://www.maratriangle.org/mara-monthly",
   "read": "2026-11-12"
  }
 ],
 "columns": [
  {
   "name": "season",
   "title": "Season",
   "description": "The year the season starts (a season runs into January or February of the next year when the herds stay)"
  },
  {
   "name": "first_groups",
   "title": "first groups",
   "description": "Date of the first small or advance groups of wildebeest recorded in the Mara, either side of the river: YYYY-MM-DD, YYYY-MM-early|mid|late, or YYYY-MM when the report gives the month only; blank when none is recorded"
  },
  {
   "name": "first_groups_resolution",
   "title": "first groups resolution",
   "description": "day, early, mid, late or month: how precisely the report dates it"
  },
  {
   "name": "first_groups_unclear",
   "title": "first groups unclear",
   "description": "true where the report wording leaves the date open (the reason is in the audit notes of the monthly report)"
  },
  {
   "name": "first_groups_report",
   "title": "first groups report",
   "description": "URL of the Mara Conservancy monthly report the date comes from"
  },
  {
   "name": "first_groups_counted",
   "title": "first groups counted",
   "description": "true where the season counts in the summaries on the page (false: see notes)"
  },
  {
   "name": "first_arrival",
   "title": "first arrival",
   "description": "Date of the first large herds of wildebeest recorded in the Mara: YYYY-MM-DD, YYYY-MM-early|mid|late, or YYYY-MM when the report gives the month only; blank when none is recorded"
  },
  {
   "name": "first_arrival_resolution",
   "title": "first arrival resolution",
   "description": "day, early, mid, late or month: how precisely the report dates it"
  },
  {
   "name": "first_arrival_unclear",
   "title": "first arrival unclear",
   "description": "true where the report wording leaves the date open (the reason is in the audit notes of the monthly report)"
  },
  {
   "name": "first_arrival_report",
   "title": "first arrival report",
   "description": "URL of the Mara Conservancy monthly report the date comes from"
  },
  {
   "name": "first_arrival_counted",
   "title": "first arrival counted",
   "description": "true where the season counts in the summaries on the page (false: see notes)"
  },
  {
   "name": "first_crossing",
   "title": "first crossing",
   "description": "Date of the first wildebeest crossing of the Mara River recorded inside the Mara: YYYY-MM-DD, YYYY-MM-early|mid|late, or YYYY-MM when the report gives the month only; blank when none is recorded"
  },
  {
   "name": "first_crossing_resolution",
   "title": "first crossing resolution",
   "description": "day, early, mid, late or month: how precisely the report dates it"
  },
  {
   "name": "first_crossing_unclear",
   "title": "first crossing unclear",
   "description": "true where the report wording leaves the date open (the reason is in the audit notes of the monthly report)"
  },
  {
   "name": "first_crossing_report",
   "title": "first crossing report",
   "description": "URL of the Mara Conservancy monthly report the date comes from"
  },
  {
   "name": "first_crossing_counted",
   "title": "first crossing counted",
   "description": "true where the season counts in the summaries on the page (false: see notes)"
  },
  {
   "name": "departure",
   "title": "departure",
   "description": "Date of the the date the report gives for the large herds leaving the Mara for the season: YYYY-MM-DD, YYYY-MM-early|mid|late, or YYYY-MM when the report gives the month only; blank when none is recorded"
  },
  {
   "name": "departure_resolution",
   "title": "departure resolution",
   "description": "day, early, mid, late or month: how precisely the report dates it"
  },
  {
   "name": "departure_unclear",
   "title": "departure unclear",
   "description": "true where the report wording leaves the date open (the reason is in the audit notes of the monthly report)"
  },
  {
   "name": "departure_report",
   "title": "departure report",
   "description": "URL of the Mara Conservancy monthly report the date comes from"
  },
  {
   "name": "departure_counted",
   "title": "departure counted",
   "description": "true where the season counts in the summaries on the page (false: see notes)"
  },
  {
   "name": "jun",
   "title": "jun",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "jul",
   "title": "jul",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "aug",
   "title": "aug",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "sep",
   "title": "sep",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "oct",
   "title": "oct",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "nov",
   "title": "nov",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "dec",
   "title": "dec",
   "description": "H large herds recorded in the Mara in the month; H* report silent, herds recorded the month before and after with no departure between; s small groups, stragglers or a few thousand only; d all left during the month; - none recorded; ? report exists but does not mention the migration; n/r no report in the archive"
  },
  {
   "name": "other",
   "title": "Other months",
   "description": "Herds recorded outside June to December, in the report's terms"
  },
  {
   "name": "notes",
   "title": "Notes",
   "description": "Why an event is left out of the summaries"
  }
 ],
 "rows": [
  {
   "season": 2001,
   "first_groups": "2001-08-late",
   "first_groups_resolution": "late",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/august-2001",
   "first_groups_counted": false,
   "first_arrival": "2001-08-late",
   "first_arrival_resolution": "late",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2001",
   "first_arrival_counted": false,
   "first_crossing": "2001-10",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/october-2001",
   "first_crossing_counted": true,
   "departure": "2001-11",
   "departure_resolution": "month",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2001",
   "departure_counted": true,
   "jun": "n/r",
   "jul": "n/r",
   "aug": "H",
   "sep": "H",
   "oct": "s",
   "nov": "-",
   "dec": "n/r",
   "other": "",
   "notes": "first groups and first arrival not counted: no report before August 2001"
  },
  {
   "season": 2002,
   "first_groups": "2002-07-late",
   "first_groups_resolution": "late",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2002",
   "first_groups_counted": true,
   "first_arrival": "2002-08",
   "first_arrival_resolution": "month",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2002",
   "first_arrival_counted": true,
   "first_crossing": "2002-08",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": true,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/august-2002",
   "first_crossing_counted": true,
   "departure": "2002-11-20",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2002",
   "departure_counted": true,
   "jun": "-",
   "jul": "s",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2003,
   "first_groups": "2003-07-late",
   "first_groups_resolution": "late",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2003",
   "first_groups_counted": true,
   "first_arrival": "2003-07-late",
   "first_arrival_resolution": "late",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2003",
   "first_arrival_counted": true,
   "first_crossing": "2003-08-late",
   "first_crossing_resolution": "late",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/august-2003",
   "first_crossing_counted": true,
   "departure": "2004-01-20",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/january-2004-1",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "H",
   "other": "Jan 2004 H (to 20th)",
   "notes": ""
  },
  {
   "season": 2004,
   "first_groups": "2004-07-early",
   "first_groups_resolution": "early",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2004",
   "first_groups_counted": true,
   "first_arrival": "2004-07-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2004",
   "first_arrival_counted": true,
   "first_crossing": "2004-07",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2004",
   "first_crossing_counted": true,
   "departure": "2004-11-late",
   "departure_resolution": "late",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2004",
   "departure_counted": true,
   "jun": "n/r",
   "jul": "H",
   "aug": "H*",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "s",
   "other": "",
   "notes": ""
  },
  {
   "season": 2005,
   "first_groups": "2005-07-30",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2005",
   "first_groups_counted": true,
   "first_arrival": "2005-07-30",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2005",
   "first_arrival_counted": true,
   "first_crossing": "2005-07-30",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2005",
   "first_crossing_counted": true,
   "departure": "2006-01-mid",
   "departure_resolution": "mid",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/january-2006-1",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "H",
   "other": "Jan 2006 H, Feb 2006 s (10,000 to 15,000), gone early Mar",
   "notes": ""
  },
  {
   "season": 2006,
   "first_groups": "2006-06-14",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2006-1",
   "first_groups_counted": true,
   "first_arrival": "2006-07-mid",
   "first_arrival_resolution": "mid",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2006",
   "first_arrival_counted": true,
   "first_crossing": "2006-07-mid",
   "first_crossing_resolution": "mid",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2006",
   "first_crossing_counted": true,
   "departure": "2006-11-15",
   "departure_resolution": "day",
   "departure_unclear": true,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2006",
   "departure_counted": true,
   "jun": "s",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "s",
   "other": "",
   "notes": ""
  },
  {
   "season": 2007,
   "first_groups": "2007-07-20",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2007",
   "first_groups_counted": true,
   "first_arrival": "2007-08-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2007",
   "first_arrival_counted": true,
   "first_crossing": "2007-07-20",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2007",
   "first_crossing_counted": true,
   "departure": "2007-12-20",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/december-2007",
   "departure_counted": true,
   "jun": "-",
   "jul": "s",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "H",
   "other": "",
   "notes": ""
  },
  {
   "season": 2008,
   "first_groups": "2008-07-04",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2008",
   "first_groups_counted": true,
   "first_arrival": "2008-07-04",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2008",
   "first_arrival_counted": true,
   "first_crossing": "2008-07-04",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2008",
   "first_crossing_counted": true,
   "departure": "2008-11-10",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2008",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2009,
   "first_groups": "2009-06-23",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2009",
   "first_groups_counted": true,
   "first_arrival": "2009-07-06",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2009",
   "first_arrival_counted": true,
   "first_crossing": "2009-07-06",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2009",
   "first_crossing_counted": true,
   "departure": "2009-11-mid",
   "departure_resolution": "mid",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2009",
   "departure_counted": true,
   "jun": "s",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2010,
   "first_groups": "2010-06-12",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2010",
   "first_groups_counted": true,
   "first_arrival": "2010-06-14",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2010",
   "first_arrival_counted": true,
   "first_crossing": "2010-06",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2010",
   "first_crossing_counted": true,
   "departure": "2010-11",
   "departure_resolution": "month",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2010",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "s",
   "other": "",
   "notes": ""
  },
  {
   "season": 2011,
   "first_groups": "2011-06-30",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2011",
   "first_groups_counted": true,
   "first_arrival": "2011-07-mid",
   "first_arrival_resolution": "mid",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2011",
   "first_arrival_counted": true,
   "first_crossing": "2011-07-mid",
   "first_crossing_resolution": "mid",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2011",
   "first_crossing_counted": true,
   "departure": "2011-11-early",
   "departure_resolution": "early",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2011",
   "departure_counted": true,
   "jun": "s",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "s",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2012,
   "first_groups": "2012-07-14",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2012",
   "first_groups_counted": true,
   "first_arrival": "2012-08-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2012",
   "first_arrival_counted": true,
   "first_crossing": "2012-07",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2012",
   "first_crossing_counted": true,
   "departure": "2012-11-early",
   "departure_resolution": "early",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2012",
   "departure_counted": true,
   "jun": "-",
   "jul": "s",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2013,
   "first_groups": "2013-06-mid",
   "first_groups_resolution": "mid",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2013",
   "first_groups_counted": true,
   "first_arrival": "2013-06-29",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2013",
   "first_arrival_counted": true,
   "first_crossing": "2013-07-early",
   "first_crossing_resolution": "early",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2013",
   "first_crossing_counted": true,
   "departure": "2013-12-early",
   "departure_resolution": "early",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/december-2013",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "s",
   "nov": "H",
   "dec": "H",
   "other": "",
   "notes": ""
  },
  {
   "season": 2014,
   "first_groups": "2014-05-27",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/may-2014",
   "first_groups_counted": true,
   "first_arrival": "2014-06-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2014",
   "first_arrival_counted": true,
   "first_crossing": "2014-06-late",
   "first_crossing_resolution": "late",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/june-2014",
   "first_crossing_counted": true,
   "departure": "2014-10-20",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/october-2014",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "-",
   "dec": "-",
   "other": "May s (from 27th)",
   "notes": ""
  },
  {
   "season": 2015,
   "first_groups": "2015-07-12",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2015",
   "first_groups_counted": true,
   "first_arrival": "2015-08-late",
   "first_arrival_resolution": "late",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2015",
   "first_arrival_counted": true,
   "first_crossing": "2015-08-late",
   "first_crossing_resolution": "late",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/august-2015",
   "first_crossing_counted": true,
   "departure": "2015-11",
   "departure_resolution": "month",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2015",
   "departure_counted": true,
   "jun": "-",
   "jul": "s",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "d",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2016,
   "first_groups": "2016-06-09",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2016-2",
   "first_groups_counted": true,
   "first_arrival": "2016-06-30",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2016-2",
   "first_arrival_counted": true,
   "first_crossing": "2016-06-29",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/june-2016-2",
   "first_crossing_counted": true,
   "departure": "2016-12",
   "departure_resolution": "month",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/december-2016-1",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "s",
   "nov": "H",
   "dec": "d",
   "other": "",
   "notes": ""
  },
  {
   "season": 2017,
   "first_groups": "2017-06-mid",
   "first_groups_resolution": "mid",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2017",
   "first_groups_counted": true,
   "first_arrival": "2017-06-late",
   "first_arrival_resolution": "late",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2017",
   "first_arrival_counted": true,
   "first_crossing": "2017-06-25",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/june-2017",
   "first_crossing_counted": true,
   "departure": "2017-09-05",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/september-2017",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "-",
   "nov": "-",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2018,
   "first_groups": "2018-07-mid",
   "first_groups_resolution": "mid",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2018",
   "first_groups_counted": true,
   "first_arrival": "2018-07-late",
   "first_arrival_resolution": "late",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2018",
   "first_arrival_counted": true,
   "first_crossing": "2018-08-mid",
   "first_crossing_resolution": "mid",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/august-2018",
   "first_crossing_counted": true,
   "departure": "2018-12",
   "departure_resolution": "month",
   "departure_unclear": true,
   "departure_report": "https://www.maratriangle.org/mara-monthly/december-2018",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "H",
   "dec": "s",
   "other": "",
   "notes": ""
  },
  {
   "season": 2019,
   "first_groups": "2019-05-29",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/may-2019",
   "first_groups_counted": true,
   "first_arrival": "2019-06-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/june-2019",
   "first_arrival_counted": true,
   "first_crossing": "2019-07-16",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2019",
   "first_crossing_counted": true,
   "departure": "2019-10-24",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/october-2019",
   "departure_counted": true,
   "jun": "H",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "s",
   "dec": "-",
   "other": "May s (from 29th)",
   "notes": ""
  },
  {
   "season": 2020,
   "first_groups": "2020-07-early",
   "first_groups_resolution": "early",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2020",
   "first_groups_counted": true,
   "first_arrival": "2020-07-16",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2020",
   "first_arrival_counted": true,
   "first_crossing": "2020-07-late",
   "first_crossing_resolution": "late",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2020",
   "first_crossing_counted": true,
   "departure": "2020-10-mid",
   "departure_resolution": "mid",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/october-2020",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "s",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2021,
   "first_groups": "2021-06",
   "first_groups_resolution": "month",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2021",
   "first_groups_counted": true,
   "first_arrival": "2021-07-20",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2021",
   "first_arrival_counted": true,
   "first_crossing": "2021-08-mid",
   "first_crossing_resolution": "mid",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/august-2021",
   "first_crossing_counted": true,
   "departure": "2021-10-late",
   "departure_resolution": "late",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/october-2021",
   "departure_counted": true,
   "jun": "s",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "s",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2022,
   "first_groups": "2022-06",
   "first_groups_resolution": "month",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2022",
   "first_groups_counted": true,
   "first_arrival": "2022-07-08",
   "first_arrival_resolution": "day",
   "first_arrival_unclear": true,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2022",
   "first_arrival_counted": true,
   "first_crossing": "2022-07",
   "first_crossing_resolution": "month",
   "first_crossing_unclear": true,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2022",
   "first_crossing_counted": true,
   "departure": "2022-09-late",
   "departure_resolution": "late",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/september-2022",
   "departure_counted": true,
   "jun": "s",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "s",
   "nov": "-",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2023,
   "first_groups": "2023-07-20",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2023",
   "first_groups_counted": true,
   "first_arrival": "2023-08-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2023",
   "first_arrival_counted": true,
   "first_crossing": "2023-07-20",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2023",
   "first_crossing_counted": true,
   "departure": "2023-09",
   "departure_resolution": "month",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/september-2023",
   "departure_counted": true,
   "jun": "-",
   "jul": "s",
   "aug": "H",
   "sep": "H",
   "oct": "-",
   "nov": "-",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2024,
   "first_groups": "2024-07-mid",
   "first_groups_resolution": "mid",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2024",
   "first_groups_counted": true,
   "first_arrival": "2024-07",
   "first_arrival_resolution": "month",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2024",
   "first_arrival_counted": true,
   "first_crossing": "2024-07-20",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2024",
   "first_crossing_counted": true,
   "departure": "2024-10-15",
   "departure_resolution": "day",
   "departure_unclear": false,
   "departure_report": "https://www.maratriangle.org/mara-monthly/october-2024",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "-",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2025,
   "first_groups": "2025-07-06",
   "first_groups_resolution": "day",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/july-2025",
   "first_groups_counted": true,
   "first_arrival": "2025-07-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/july-2025",
   "first_arrival_counted": true,
   "first_crossing": "2025-07-25",
   "first_crossing_resolution": "day",
   "first_crossing_unclear": false,
   "first_crossing_report": "https://www.maratriangle.org/mara-monthly/july-2025",
   "first_crossing_counted": true,
   "departure": "2025-11-early",
   "departure_resolution": "early",
   "departure_unclear": true,
   "departure_report": "https://www.maratriangle.org/mara-monthly/november-2025",
   "departure_counted": true,
   "jun": "-",
   "jul": "H",
   "aug": "H",
   "sep": "H",
   "oct": "H",
   "nov": "s",
   "dec": "-",
   "other": "",
   "notes": ""
  },
  {
   "season": 2026,
   "first_groups": "2026-06",
   "first_groups_resolution": "month",
   "first_groups_unclear": false,
   "first_groups_report": "https://www.maratriangle.org/mara-monthly/june-2026-25-years-of-mara-conservancy",
   "first_groups_counted": true,
   "first_arrival": "2026-08-early",
   "first_arrival_resolution": "early",
   "first_arrival_unclear": false,
   "first_arrival_report": "https://www.maratriangle.org/mara-monthly/august-2026",
   "first_arrival_counted": false,
   "first_crossing": "",
   "first_crossing_resolution": "",
   "first_crossing_unclear": false,
   "first_crossing_report": "",
   "first_crossing_counted": false,
   "departure": "",
   "departure_resolution": "",
   "departure_unclear": false,
   "departure_report": "",
   "departure_counted": false,
   "jun": "s",
   "jul": "?",
   "aug": "H",
   "sep": "?",
   "oct": "H",
   "nov": "n/r",
   "dec": "n/r",
   "other": "",
   "notes": "first arrival not counted: the July 2026 report does not mention the migration; first crossing not counted: no crossing recorded in the Mara; the July and September 2026 reports do not mention the migration; departure not counted: season still open: no November 2026 report on 12 November 2026"
  }
 ]
}