We have previously shared information about our involvement in the Project Monarch Collaboration, which is led by the Cape May Point Arts & Science Center (CMPASC) and Cellular Tracking Technologies (CTT), and includes more than 25 organizations. For complete background information, please see our main Radio Tagged Monarchs page.

2025-2026 SEASON UPDATES

The race is on!

As part of this project, more than 600 BlūMorpho solar-powered radio transmitters have been deployed this migration season, including more than 500 during the fall 2025 migration and another 150+ ahead of the spring 2026 migration.

This webpage serves as a repository for updates by Monarch Watch Director Kristen Baum that have been posted to Dplex-L (our email discussion list) and social media (FB, IG) about the race as it has developed over time. We will continue to add more information as time allows.

APRIL 14, 2026

April 14, 2026. ROS014 is approaching Texas. She traveled approximately 346 miles from her last location on Apr. 11 to her last location at the end of today. She was tagged at El Rosario on Feb. 11. Prior to Apr. 9, her detections were all in the vicinity of the overwintering sanctuary. Directional northward movement has only been detected over the past week. Very interesting data!

APRIL 13, 2026

April 13, 2026. ALB004 reached Texas today. MW024 was the last monarch to reach the US on Mar. 29, so it has been over two weeks since the last arrival. ALB004 crossed the farthest to the west of any of the radio tagged monarchs. The path of CRE006 is also included, since she was previously the farthest to the west. She was last detected on Mar. 21. ALB004 brings the total to 19 radio tagged monarchs that have reached the US, with 15 females and 4 males.

APRIL 12, 2026

April 12, 2026. The activity of the overwintering monarchs with radio tags has continued to slow down. ALB004, a female tagged on Feb. 20 at the Albarranes colony, has been making steady progress towards Texas over the past week. It will be interesting to see if she is detected in Texas over the coming days, which would represent a very late arrival to Texas.

APRIL 7, 2026

April 7, 2026. Activity is slowing down for the radio tagged monarchs that we have been following. We wanted to look at locations for entering Texas. The arrows on the map below show the last detection in Mexico to the first detection in the US. Chip’s map of the interior and coastal pathways is also included. The most recent four arrivals from Mar. 26 (CHI009, MES005, MES011) and Mar. 29 (MW024) are represented by the four arrows the farthest to the north in Texas.

APRIL 3, 2026

April 3, 2026. MW024 was detected in Oklahoma today. She is the second radio tagged monarch to reach Oklahoma, following ROS032 (a male) that reached Oklahoma on Mar. 25, but hasn’t been detected since then. MW024 was last detected on Mar. 30 near Abilene, Texas, and traveled 176 miles with no detections. If you zoom in on the location of MW024, you will notice that she was last detected in a wind farm.

There have also continued to be some directional movements over the past couple days at the overwintering sanctuaries in Mexico. For example, ALB004 and ALB007 are both females tagged at the Albarranes colony on Feb. 20. I’m also highlighting LPM097, a female released at Long Point in Ontario on Sep. 29, 2025 (!!!). It will be interesting to see if there continue to be directional movements.

APRIL 2, 2026

April 2, 2026. As we move into early April, expectations for additional radio tagged monarchs reaching the US have declined. I thought it would be interesting to look at the greatest distances traveled and the greatest number of days between last detections in Mexico and first detections in the US, with the idea that might place some bounds on remaining expectations. ROS011 wins the award for greatest distance traveled between last detection in Mexico and first detection in the US and she comes in second for number of days between detections. CHI009 wins the award for greatest number of days between last detection in Mexico and first detection in the US, and he comes in second for distance traveled between detections. If you notice that my distance calculations are a little different from previous estimates for these monarchs, it is because I used a slightly different earth radius multiplier for my great circle distance calculation for estimating the distance between two points.

MARCH 31, 2026

March 31, 2026. Today we are sharing an updated map of current locations of the radio tagged monarchs in the US. There are 4 males and 14 females, for a total of 18 monarchs, with 15 tagged at the overwintering sanctuaries in Mexico and 3 tagged during the fall migration. Individuals that have been detected since the last group map are bolded so you can more easily identify movements, and the previous group map is included to allow for easier comparisons. Yesterday we posted about XSTI009 moving into Florida. She returned to Georgia today. ROS011 was also previously recorded in Florida, but she continues west and most recently to the northwest.

MARCH 30, 2026

March 30, 2026. XSTI009 was detected in Florida yesterday. You will recall that ROS011 was the first radio tagged monarch to be detected in Florida on Mar. 22, but she returned to Alabama on Mar. 24 and has continued west. ROS011 is now west of her first detection location in the US/Louisiana. CHI016 was last detected Sunday (not yesterday), but she was close to the Arkansas border with Missouri. XSTI009 is the monarch farthest to the east, and CHI016 is farthest to the north. All three of the monarchs highlighted today have more than 1000 detections, and only the most recent 1000 detections are shown in the app. Recall that the red stars represent the release location, the monarchs represent the current location, and the blue dots represent detection locations.

MARCH 29, 2026

March 29, 2026. MW024 was detected in Texas today! MW024 is the third fall tagged monarch to be detected in the US. She was tagged on September 27 in Lawrence, Kansas. She was last detected north of Ciudad Victoria on March 24. You may have noticed that is a common pattern, where a radio tagged monarch is detected near Ciudad Victoria, several days pass with no detections, and then they are detected in Texas. For example, we saw that pattern last week with MES005 and MES011. That pattern likely reflects the path of the monarchs relative to the distribution of Bluetooth devices.

MARCH 28, 2026

March 28, 2026. XSTI009 is the radio-tagged monarch that has been detected the farthest to the east. She reached Georgia on March 23 and has been traveling to the southeast. She is currently near the border with Florida. ROS011 has continued to move west. As you may recall, she was first detected in the US in Louisiana on March 18. She then moved east through Mississippi and Alabama, reaching the Florida panhandle. She then made a U-turn and is now back in Louisiana near where she was first detected on March 18.

And lastly, with winds out of the east, there have been westward movements by some of the monarchs still located near the overwintering sanctuaries. The map shows the detections for CRE007, as well as the current locations for the other monarchs that were detected today.

The winds will shift to being out of the southeast in northern Mexico and south in Texas/Oklahoma tomorrow, so watch for additional movements.

MARCH 27, 2026

March 27, 2026. For today, we are sharing an update of current locations of the radio tagged monarchs in the US. There are 4 males and 13 females, for a total of 17 monarchs. Fifteen of those monarchs were tagged at the overwintering sanctuaries in Mexico and two during the fall migration, all as part of the Project Monarch Collaboration. The key provides tagging locations, the blue dots represent females, and the orange dots represent males. The dates are for last detection based on relevant time zones.

MARCH 26, 2026

March 26, 2026. Three more radio tagged monarchs arrived in Texas today. The biggest surprise was CHI009. He was last detected in Mexico on Mar. 10 and traveled approximately 735 miles without being detected until north of College Station, Texas. MES005 and MES011 were both last detected near Ciudad Victoria in Mexico on Mar. 22 and traveled approximately 450-500 miles before being detected to the northwest and west of Austin, Texas.

MARCH 25, 2026

March 25, 2026. ROS032 was detected in Oklahoma today. He is the first radio tagged monarch to be detected in Oklahoma this spring and is the farthest north of the radio tagged monarchs. If you check out adult monarch first sightings on Journey North, he is also the farthest to the west in Oklahoma of any reported monarchs. Don't forget to submit your first sightings to Journey North! ROS011 continued to move west today. She was detected in Mississippi. If you recall previous updates, she had already traveled east from Louisiana to the panhandle of Florida, but she is now moving to the west and back the way she came.

MARCH 24, 2026

March 24, 2026. ROS011 was detected back in Alabama today. She was first detected in Florida on Mar. 22, she continued farther into Florida on Mar. 23, but she returned to Alabama today.

MW024 was detected again in Mexico. She is more than 1/2 the way to Texas, but she hadn’t been detected since Mar. 19. MW024 is a fall tagged monarch that we tagged in Lawrence, Kansas on Sep. 27. There are two other fall tagged monarchs that have been detected in Mexico over the last week, including NOK019 (last detected Mar. 21) and MW005 (last detected Mar. 19), and a few more if you go back another week. The fall tagged monarchs provide interesting data on fall versus spring origins, paths, and destinations, and it would be exciting if we can add a few more individuals to what we have learned so far from XSTI009 and JMU004.

MARCH 23, 2026

March 23, 2026. There wasn't a lot of movement today. However, XSTI009 was detected in Georgia, and is now the farthest to the east. Here is a map of current locations of the radio tagged monarchs that migrated from the overwintering sanctuaries in Mexico to the US in March, which includes 2 males and 12 females.

MARCH 22, 2026

March 22, 2026. ROS011 was detected in Florida today! ROS007 reached Texas along the interior pathway, and ROS032 is on a trajectory towards Oklahoma. All three of these monarchs were tagged at El Rosario on Feb. 11.

MARCH 21, 2026

March 21, 2026. ROS011 and XSTI009 reached Alabama today! ROS011 is very close to the panhandle of Florida, while XSTI009 is on a trajectory towards Georgia. CRE006 continued on a path to the northwest that doesn’t appear to be influenced by winds, but additional detections will provide more information.

MARCH 20, 2026

March 20, 2026. CRE006, OXT004, and ROS032 entered Texas today. That gives us 11 females and 2 males (JMU004 and ROS032) that have reached Texas. There are currently 9 radio tagged monarchs in Texas, 1 in Arkansas, and 3 in Mississippi. There have also been detections for 2 monarchs in Louisiana that have moved on into Mississippi, and another that may have passed through the northwest corner on the way to Arkansas. The three that moved into Texas yesterday, along with OXT010, for which we don’t have a complete track in the app, have entered along the area that Chip refers to as the montane or interior pathway. Interestingly, CHI016 entered Texas between those two pathways. Chip has previously mentioned that the interior pathway appears to be used when temperatures along the coastal pathway are too high.

MARCH 19, 2026

March 19, 2026. Today was another interesting day! JMU004 reached Texas. He was near Austin by the end of the day. JMU004 is the first male radio tagged monarch to reach Texas, and the second fall tagged monarch to reach Texas (XSTI009 was first with a detection on Mar. 14). JMU004 was originally tagged in Virginia on Sep. 23. He has traveled more than 3,000 miles! Also, don’t forget that JMU004 was the first radio tagged monarch to be detected within the boundaries of a known overwintering site. ROS006 and ROS011 both continued east and were detected in Mississippi.

MARCH 18, 2026

March 18, 2026. Yesterday was an interesting day! ROS006 was detected again after minimum temperatures below freezing in Arkansas. ROS011 showed up near Baton Rouge, Louisiana after last being detected on Mar. 10 in Mexico. We don’t know what path she took to get there. Part of the path for OXT010 is missing in the app, but she entered Texas on Mar. 14 farther north than other monarchs so far. She is currently east of Dallas. JMU004 was detected again after not being detected since Mar. 10. He is currently very close to Texas. He has over 2000 detections, so the first part of his path isn't visible in the app. We are still waiting for the first radio tagged male to be detected in Texas.

MARCH 17, 2026

March 17, 2026. There wasn’t a lot of movement today due to poor movement conditions, but we are providing an update on MW005 and MW024. Both traveled approximately 1,380 miles from Lawrence, Kansas to the overwintering sanctuaries (El Rosario for MW024, Cerro Pelón for MW005) and were last detected on Monday, March 16. MW005 has been featured a few times as we initially thought he didn’t make it out of Texas with his last detections being on Oct. 31 at Matagorda Island. He showed up at the overwintering sanctuaries on Jan. 6 and then was detected numerous times through Feb. 19. After several weeks with no detections, he was detected again on Mar. 10, but then he moved west with some of the strong east winds. We thought he was correcting course on Mar. 13, but then he moved to the southeast. MW024 has shown some northward movement, and she is now 123 miles to the northeast of her overwintering location.

MARCH 16, 2026

March 16, 2026. With strong north winds (blowing to the south) and cooler temperatures in Texas, movement was limited for the radio tagged monarchs farthest to the north. As an update to yesterday’s post, ROS008 (female) was detected in Texas today, but ROS026 (male) was not, so we are still waiting for the first male to be detected in Texas. That brings the total to 7 monarchs that have been detected in Texas (Mar. 10: OXT006; Mar. 14: ROS006, XSTI009; Mar. 15: ALB010, ALB009, CHI016; Mar. 16: ROS008), but don't forget that ROS006 has moved through Texas and was detected in Arkansas on Mar. 15.

There were some interesting movement patterns today. ALB010 showed a hook to the south, likely reflecting the strong north winds. OXT003 was previously highlighted for a movement to the west in Mexico and was detected about 148 miles to the north today. And lastly, you will notice a new prefix in the app. OJO monarchs were tagged at the Ojo de Agua colony on March 9 by our colleagues with the National Commission of Natural Protected Areas (CONANP) and World Wildlife Fund – Mexico (WWF-MX). OJO004, a female, is now 238 miles from her release location and along the east coast.

MARCH 15, 2026

March 15, 2026. ROS006 made another impressive move today. She was detected 353 miles away in Arkansas (!!!), using end of day to end of day detections. Three more radio tagged monarchs reached Texas, including ALB010, ALB009, and CHI016. ROS008 and ROS026 are very close to being detected in Texas. If ROS026 is detected in Texas, he would be the first male detected in Texas. The image below (left panel) includes the last date of detection and male or female. ROS006 is shown on a separate image (middle panel) to show her big move. XSTI009 is also shown (right panel) as she had many detections while moving through Houston. If you view her in the app, make sure to zoom in all the way to see much more detail than is shown here.

MARCH 14, 2026

March 14, 2026; Update #3. In addition to ROS006 and XSTI009 being detected in Texas, there were also lots of detections for other radio tagged monarchs. Here is a map of the leading edge in Mexico with dates of last detections. The locations of the ATL (Atlautla) monarchs are also provided as that colony is located at the southeast corner of the overwintering sanctuaries. And lastly, ROS006 moved more than 138 miles from her first detection in Corpus Christi, Texas to her ending location north of Hallettsville, Texas. By car, that would be more than a 2.5-hour drive.

March 14, 2026; Update #2. And XSTI009 is in Texas! The full path isn’t available in the app because she has 1,171 detections, but an overview of her fall migration path is included on the image. XSTI009 is the first monarch that was tagged this past fall to make it back to Texas after overwintering in Mexico.

March 14, 2026; Update #1. ROS006 joined OXT006 in Texas today! Two radio tagged monarchs have now been detected in Texas. Both are females, and both were tagged at the overwintering sanctuaries by our amazing Mexican partners who are part of the Project Monarch Collaboration. ROS006 was tagged at El Rosario and OXT006 was tagged at Oxtotilpan. And there are others close behind! We are still waiting for the first fall tagged monarch to be detected in Texas and XSTI009 is VERY close.

MARCH 13, 2026

March 13, 2026. There were detections to the north for several radio tagged monarchs today, including CHI016, CRE004, ALB016, and XSTI009. Of that group, all were tagged in February at the overwintering sanctuaries in Mexico, except for XSTI009, which was tagged last fall in Oklahoma. CHI016, CRE004, and XSTI009 all show movement to the northeast, with CRE004 making a noticeable shift to the northeast. We will be watching to see if ALB016 also shifts to the northeast, to enter Texas along the coastal migration route.

MARCH 12, 2026

March 12, 2026. There were strong east winds (blowing to the west) today. MW005 was detected 119 miles to the west, while OXT003 was detected 224 miles (!!!) away from where it ended the day before. Dates of last detection are shown for some of the other monarchs on the group image. The graph, shared by Chip, shows wind speed and direction.

MARCH 11, 2026

March 11, 2026. JMU004 wasn’t detected today. However, XSTI009, a female tagged on Oct. 8 in Oklahoma, is now close behind after moving 187 miles between detections on Mar. 8 and Mar. 11. She is closely following her path from this fall, at least for now, with the fall path represented by the dashed lines. A few monarchs, including ROS005, ATL016, and ATL019, are showing movement to the northeast. It is possible they are following the coastal spring migration route, which is shown on the map to the left, but more detections are needed to evaluate this possibility.

MW005 showed northward movement today. You may recall from this past fall that we initially thought MW005 didn’t make it out of Texas with his last detections being on Oct. 31 at Matagorda Island. He showed up at the overwintering sanctuaries on Jan. 6 and then was detected numerous times through Feb. 19. After several weeks with no detections, he was detected again on Mar. 10 and Mar. 11 and has moved 47 miles.

MARCH 10, 2026

March 10, 2026. And we have a winner! OXT006 was released on Feb. 21 and last detected on March 3. She is now northeast of Victoria, Texas!

While OXT006 won the race to Texas today, we are still watching and learning more from the radio tagged monarchs. OXT006 was tagged in Mexico in February, so it will be exciting when the first monarch that was tagged this past fall makes it to Texas. That will also confirm a huge success for the process of attaching the tags! JMU004 is currently the main contender, and you will also recall that JMU004 was the first radio tagged monarch to be detected within a known overwintering site (and was featured in The New York Times article that introduced the project). JMU004 is also in second place overall after he passed the last recorded location of CHI010 yesterday. MES016 is close behind in third place overall. That said, after OXT006 moved 533 miles between detections on March 3 and March 10 to be the first radio tagged monarch to be recorded in Texas, we won’t be surprised if the lineup changes.

Also notice the cluster of ROS (El Rosario) monarchs in the image above for today. Make sure to check out the ATL (Atlautla) monarchs that now show up in the app. These monarchs were tagged last week by the Monarch Butterfly Biosphere Reserve Directorate team, in coordination with WWF-Mexico, Izta-Popo National Park, and the Atlautla Communal Lands.

MARCH 9, 2026

March 9, 2026. Today was another busy day on the Project Monarch Science app. JMU004 moved 134 miles from his last detection on Mar. 8 to his last detection on Mar. 9. MES015, a female tagged in Mexico a little over a month ago, moved 93 miles. There were lots of other movements as well, but no monarchs have been detected north of the location of CHI010 yet. CHI010 was last detected on Mar. 7 and is about 400 miles from Eagle Pass, Texas. JMU004 is about 38 miles south of CHI010.

Don’t forget to go outside and report your “first sighted” observations to Journey North! When you check out the first sightings of adult monarchs, you can view pictures for some of the observations. You can evaluate if you think they are “fresh” monarchs that may be the offspring of monarchs that overwintered along the Gulf Coast or if they have wing scale loss expected for those that have traveled many miles to and from the overwintering sanctuaries in Mexico.

MARCH 8, 2026

March 8, 2026. There were lots of detections today, but the composition of the leading edge hasn’t changed much or added many monarchs. CHI010 is still out front, followed by OXT006 and ROS001, and then ROS017 and ALB015, which are joined by CHI013. CHI013 made a big move with her detection yesterday after she was last recorded on March 3. There was also a noticeable wave of OXT and ALB monarchs leaving their overwintering sanctuaries. The northward movement of monarchs that were tagged this past fall, including JMU004 (tagged in Virginia on Sept. 23), XSTI009 (tagged in Oklahoma on Oct. 8), and JD-EFTATX010 (tagged in Texas on Oct. 24) are highlighted in the image for today.

MARCH 7, 2026

March 7, 2026. The leaderboard shows the monarchs that are leading the pack. CHI010 moved 81 miles since the last detection on March 6! CHI004 is also highlighted today for his interesting path. He is currently located 72 miles west of his release location.

MARCH 6, 2026

March 6, 2026. The leaderboard shows the monarchs that are leading the pack. The date of last detection and male/female are included for each monarch. You will notice there are lots of females on the leaderboard! CHI010 (a male) is in the lead. ROS001 (a female) is close behind and has made big moves over the past few days.

MARCH 5, 2026

March 5, 2026. CHI010 and CHI018 were both tagged at Sierra Chincua on Feb. 11. CHI010 first showed clear directional movement on March 2 when he was detected about 40 miles to the north. Since then, distances between end of day detections have been about 40 miles (March 3), 28 miles (March 4), and 58 miles (March 5). CHI010 is currently less than 5 miles south of OXT006. Recall that OXT006 has the detection farthest to the north, and she was last detected on March 3. CHI018 moved west starting in mid-February and made a turn to the north yesterday. CHI018 has moved approximately 311 miles (segment to segment) compared to the 166 miles moved by CHI010. The Southwest Monarch Study has previously documented the movement of monarchs in Arizona to overwintering sites in both Mexico and California, but it is not known if monarchs that overwintered in central Mexico enter Arizona in the spring.

MARCH 4, 2026

March 4, 2026. There were detections of quite a few monarchs with northward movements with select examples highlighted. ALB006 was tagged at the San Antonio Albarranes colony (ALB), which you will notice is southeast of the Sierra Chincua (CHI) and El Rosario (ROS) colonies. If you look closely at the track of ALB006, you will notice that she stopped by the Monarch Butterfly Biosphere Reserve on March 1.

MARCH 3, 2026

March 3, 2026. By the end of the day, CHI018 was detected the farthest to the West (276 miles) and OXT006 was detected the farthest to the North (197 miles) of any of the Blū+ tagged monarchs. Both monarchs are females that were tagged at the overwintering sanctuaries in February. The red star represents the locations where they were tagged and the blue dots represent detections. Distance estimates are from release locations to current locations.

MARCH 2, 2026

March 2, 2026. There is a group update for today using the current app image of CHI018. Recall that monarchs with the CHI prefix were tagged at the Sierra Chincua sanctuary (represented by the red star) in Michoacán. The blue dots represent the path of detections of CHI018. The orange dots represent other monarchs showing the most directional movement to the north and west; the orange dots are an approximation of the last detection and less precise than the blue dots. Each monarch is labeled with the ID, female or male (if the information pulled up), and the last date of detection. The ones with blue text labels were all detected today. OXT006 moved less today (about 10 miles) than in other recent days, but she is now the monarch detected the farthest north.

MARCH 1, 2026

March 1, 2026. The update today is about MW007. He was released in Lawrence, Kansas on September 26. He was detected north of Lawrence later that same day, and then again on October 6. The lack of detections from September 27 to October 5 likely reflects lack of movement due to winds out of the south. He was then detected again on November 12 back in Lawrence, Kansas, or at least his tag was detected. The detections from November through yesterday would be of the tag, not a live butterfly. The tag has sporadically been detected from Nov. 12-14, Feb. 6-9, 11, 13, 16-19, 28, and Mar. 1. The detections are shown in the image below.

The group image from yesterday is also updated. This is a screen capture of detections for CHI018 with orange dots for other monarchs showing the most directional movement to the north and west. CHI018 and OXT006 were both detected today. CHI014 still has the farthest north detection, but she hasn’t been detected since Feb. 24. OXT006 is now almost as far north as CHI014 with a move of 25 miles today.

FEBRUARY 28, 2026

February 28, 2026. The update for today is a screen chapter of detections for CHI018. The orange dots were added to represent other monarchs showing the most directional movement to the north and west. Labels include the monarch ID, female or male (only one male in the image!), and the last date of detection. OXT006 moved 59 miles yesterday, and she made another big move of 62 miles today.

FEBRUARY 27, 2026

February 27, 2026. A Correo Real Facebook post highlights the Blū+ tags deployed at the overwintering colonies in Mexico. These are the monarchs with the ALB, CHI, CRE, MES, OXT, and ROS prefixes in the Project Monarch Science app. The CHI monarchs were tagged at the Sierra Chincua sanctuary in Michoacán. The OXT monarchs were tagged at the San Francisco Oxtotilpan colony at the Cerro del Amparo sanctuary in the State of México. CHI004 and CHI018 both headed west, while OXT006 headed north and OXT017 is currently about 27 miles south of his original release location.

FEBRUARY 26, 2026

February 26, 2026. JMU011 is still showing the most directional movement of those tagged last fall. The table included in the image shows the number of miles traveled from the last detection one day to the last detection the next day. JMU011 is also intersecting the path she took this past fall.

If you are watching the Blū+ tagged monarchs that are part of the western population, there are lots of interesting patterns in California as well. Here are tracks for ML003_Xerces and ML017_Xerces. Both are females released at the same location but moving in different directions.

FEBRUARY 25, 2026

February 25, 2026. Movement in the vicinity of the overwintering sanctuaries in Mexico was limited again today. JMU011 and PP0017 are females. PP0017 has 1172 detections, so only the most recent 1000 detections are shown in the app.

FEBRUARY 24, 2026

February 24, 2026. Movement in the vicinity of the overwintering sanctuaries in Mexico was limited again today. CHI014 was detected the farthest north of all Blū+ tagged monarchs this year and is now 125 miles from her release location. JMU011 appeared to show a path correction to the NE and she is the farthest north of the monarchs tagged this past fall.

FEBRUARY 23, 2026

February 23, 2026. CHI007 showed the most obvious movement today and was detected even farther west. While some of us have been waiting for a path correction, Gail Morris with the Southwest Monarch Study and a Monarch Conservation Specialist with Monarch Watch, pointed out that perhaps he is headed to Arizona. That is an excellent point, and the coastline is included in the image below.

FEBRUARY 22, 2026

February 22, 2026. The update for today is in the form of a blog post and includes some impressive movements to the west (not the north!) that are presumably wind related. However, make sure to also read the information for tomorrow (February 23, 2026) in combination with that post.

FEBRUARY 21, 2026

February 21, 2026. This post is about northward movement by XSTI, a monarch tagged this past fall during the fall migration. XSTI was tagged on Oct. 6 in Stillwater, Oklahoma. XSTI went undetected from Nov. 11 to Jan. 3 and then was detected multiple times in January. XSTI then headed north on Feb. 20, traveling about 40 miles that day and stopping at the northern edge of the Monarch Butterfly Biosphere Reserve. XSTI has the longest distance moved toward the north for a fall tagged monarch so far.

FEBRUARY 20, 2026

February 20, 2026. There were no detections today for ROS012, but she still has the farthest north detection. The monarchs with the "CRE" prefix were tagged on Tuesday by our colleagues with the National Commission of Natural Protected Areas (CONANP) and World Wildlife Fund – Mexico (WWF-MX) at the Crescencio Morales colony at Lomas de Aparicio. The movements by CRE002 and CHI014 are shown. For reference, San Juan del Río (where CHI014 was last detected) is about 180 miles southwest of where the coastal route and interior route separate.

FEBRUARY 19, 2026

February 19, 2026. There were no detections for ROS012 today, but CHI005 and CHI007 had detections showing movement to the northeast. The CHI prefix indicates the monarchs were tagged at Sierra Chincua and ROS is for El Rosario.

FEBRUARY 18, 2026

February 18, 2026. If anyone wants an update on the Blū+ monarchs that we tagged at Monarch Watch in Lawrence, Kansas this past fall, you can check out our most recent blog post.

To follow the monarchs recently tagged at the overwintering sanctuaries in Mexico, search for “CHI" or "ROS" or "MES". These are the monarchs tagged by World Wildlife Fund – Mexico (WWF-MX), the National Commission of Natural Protected Areas (CONANP), Cape May Point Arts & Science Center (CMPASC), and Cellular Tracking Technologies (CTT).

ROS012 traveled 66 miles from the last observation on Tuesday (Feb. 17) to the last observation from today (Feb. 18).

PROJECT MONARCH COLLABORATION

More than 25 research organizations make up the Project Monarch Collaboration. We’re excited that we could participate in what’s been an amazing contribution to science – and also a lot of fun! We’ve enjoyed sharing ideas, information, questions, answers, and other experiences with so many dedicated scientists.

Logos of Project Monarch Partners.