California monarch counts remain low

Western Monarch Update

By Gail Morris, Southwest Monarch Study coordinator

Volunteers are searching for monarchs along known coastal California overwintering sites as part of the mid-season monarch count coordinated by the Xerces Society. This year, the count takes place from Nov. 16 to Dec. 8. 

This is the premier period of the annual monarch count that provides the actual number of monarchs used as a point of comparison from year to year. Although the official numbers have not yet been released, an earlier count indicated drastically lower numbers of monarchs returning to California. 

We are all waiting for the final numbers from all the sites that reveal the larger picture of the overwintering population in California. Monarchs now lose the urge to migrate and we look forward to hearing the final tallies.

Reports from the Field

Seasoned reporters in the field give us a glimpse of monarch activity during the winter season. Currently, the largest monarch numbers are found in the northern realm of overwintering sites.

Stephanie Turcotte, Pacific Grove Monarch Sanctuary in California

We counted yesterday, 11/29/24, in Pacific Grove, California. Unfortunately, our numbers dipped again. Our total count was 107 monarchs. Perhaps that is why I delayed reporting. (In contrast: 6,158 on 12/1/23 and 14,700 on 11/25/22)

It was a very cool 38 degrees. All the monarchs we found were in the trees, no grounders or fliers, mostly scattered. There was only the one eucalyptus tree, just before the nectar beds in the western end of the grove, that had a sizable cluster. 

There were approximately 64 in that tree and four in the eucalyptus standing next to it. There were a total of six trees (three eucalyptus in the south/southwest boundary and one Monterey pine; two eucalyptus in the western boundary). 

In the southern boundary, these monarchs were on eucalyptus branches extending into the neighbors’ yards and getting the earliest sun. We walked through the entire interior area and in the northern end (where the monarchs still have protection from wind) and did not find a single monarch.

I have attached a photo from the interior of the grove looking east (you can see it by scrolling to the top of the page). What struck me while standing there is how open it is. There was an 11-mile-per-hour wind and you could feel it blowing through the middle. There is no doubt that the habitat has changed, so then we expect the monarchs to adapt. We checked the neighbors’ yards where they had roosted in 2016-2019. There were no monarchs there either that we could see. 

We shall see what happens next week.

Diana Magor, Santa Cruz, California

The survey done on Nov. 29 resulted in a count of 1,307 monarchs, slightly up from last week. 

All but 44 were clustered on the south side of Monterey Cypress trees on the south side of the sanctuary. I decided to do the count in the afternoon since the previous day (Thanksgiving) Dr. David James, John Dayton, Dr. Beth Bell and I had good views of clustered monarchs in the early afternoon, with an estimate of over 1,100, and some tags found.

Then, on Dec. 1, Beth Bell and I found two more tags, resulting in a total to date of seven of the nine tags from Oregon found in California being found at Lighthouse Field so far this season. 

The numbers found at Natural Bridges on Nov. 28 were approximately 150 to 200, way down from their high of 2,150 in late October. Numbers at Moran Lake are fluctuating but were estimated last week at 300 to 400 and Branciforte 15 to 25 (all flyers). As far as we know, Lighthouse Field has the largest number of monarchs in California at this moment. Last year on Dec. 2, 2023, my count was 8,511, and that was not the highest count in the state.

So far, seven tags have been found and identified at Lighthouse Field, all released from Oregon in early to mid-September. Two more tags were found earlier in Mill Valley and Santa Barbara. All of the tags but one were raised on native milkweed, tagged and released from The Elkton Community Education Center in Elkton, Oregon. The other, found on Nov. 28 by David James at Lighthouse Field, was from Talent, Oregon. 

Yellowjacket wasps have been harassing, killing and eating monarchs at Lighthouse Field in the early morning. They come out of nest holes in the ground and fly up into the clusters, disturbing them and causing some to fall to the ground. 

The monarchs are unable to fly and are attacked immediately by the wasps, which bite the backs of the head, eat the head, then thorax and sometimes the abdomen. At least 15 and probably more like 20 have been found partly or mostly eaten by the wasps in the last three days.  We managed to rescue a few and transfer them to sunny spots where they warm up enough to fly. I have requested that the Parks Department install wasp traps. We are also trying to locate the nests. 

The weather has been relatively warm in Santa Cruz so far this fall. No rain is expected for a couple of weeks. The monarchs are nectaring on the blue gum eucalyptus flowers, which have recently begun to open.”

Wanted: Monarch Sightings

Thank you to Stephanie Turcotte and Diana Magor for their reports from the California overwintering sites.

You can report your sightings of adult monarchs, eggs, or larvae to Journey North. Your detailed description of what you see can include, but is not limited to, the monarch’s gender and activity. If known, include the type of flowers if they are nectaring or milkweed type if laying eggs. Photos are encouraged and welcomed with all your reports.

Gail Morris is the Coordinator of the Southwest Monarch Study (www.swmonarchs.org). She is also a Monarch Watch conservation specialist, the vice president of the Central Arizona Butterfly Association and sits in several western working groups. The Western Monarch News is based on comments provided to Gail Morris. We hope to increase the number of sightings and therefore photos and comments entered into Journey North. We rely on the volunteers who communicate regularly with Gail and who agree to participate in our effort to increase awareness of the population of western monarchs. You can reach her at gail@swmonarchs.org

An update from Mexico

By Estela Romero, Journey North writer

Sierra Chincua Sanctuary is keeping steady conditions, showing a small but well-concentrated colony, with good-looking and good-sized clusters, being considered the only colony in the area up to now.

But, what is going on in El Rosario?

Our unpredictable, extraordinary monarchs are surprising us now!

We are now celebrating that the colony in El Rosario that is open to us visitors has changed, presenting a gradual population concentration.

'They’ve kept flying all over our region since their arrival now; locals have seen monarchs flying, sometimes in rather high numbers during the day at ratios as far as 25, 30 and 40 kilometers between Sierra Chincua Sanctuary - further north - and Cerro Pelón Sanctuary - further south - alongside driving main roads, nectaring in far away flower and nature patches and even cascading down among town streets in local villages… now part of them have decided to slow down and to start clustering,' El Rosario guides told me.

El Rosario EJIDO authorities and local guides assure, on the other hand, that there is a second colony already well-formed at a much higher elevation, in La Virgencita location, where the population density is several times larger:

'Due to the altitude and far more difficult hiking, besides the exclusivity of the site for specific research, this shall not be accessible to our visitors.  Later in the season, before the spring comes, at least part or even most of it could move down and join this minor population down here. We might have then a great February,' local ejidatarios added.

Temperatures are rising drastically day-by-day, reaching 20 degrees Celsius and even warmer if we go further south; the sun’s light intensity can hurt one’s sight, which could be a reason for disturbance and somewhat over-active monarch behavior. 

At night, on the other side, temperatures drop drastically to freezing points, specially at the overwintering spots in Sierra Chincua and El Rosario, typically expected as the winter approaches.

So far, it seems that the season is evolving to a point of normality and that colonies at each sanctuary shall present gradual normal changes as the season progresses unless a sudden climate event modifies the current status.

Visiting monarch sanctuaries in central México presents an opportunity to enjoy the exceptional great migration; it shall also be the chance to reflect in singular gratitude for being witnesses of this miracle of life and the miracle of nature as mankind knows it today.

Estela Romero

Journey North

Angangueo, Michoacán, México

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El Santuario Sierra Chincua mantiene condiciones estables con una colonia pequeña pero bien concentrada, mostrando perchas muy saludables, densas y de buen tamaño, siendo considerada hasta ahora como la única colonia en toda esta área. 

Pero que sucede en el Santuario El Rosario?

Nuestras impredecibles, extraordinarias Monarcas nos sorprenden ahora!

¡Estamos celebrando que la colonia de El Rosario -abierta a nosotros como visitantes- ha cambiado ahora presentando una gradual concentración de población!

“Se han mantenido volando desde su llegada; todos hemos visto Monarcas volando, algunas veces en cantidades considerables en radios de hasta 25, 30 y hasta 40 kilómetros a la redonda entre los Santuarios de Sierra Chincua y Cerro Pelón a los lados de carreteras y en busca de néctar en floración y áreas naturales alejadas e incluso bajando por las calles de algunos de nuestros pueblos… ahora, cierta parte de ellas ha decidido detenerse y comenzar a hibernar,” comentaron los guías de El Rosario.

Las autoridades del EJIDO del El Rosario y los guías locales aseguran, por el otro lado, que hay una segunda colonia bien definida a una elevación mucho mayor en la localidad de “La Virgencita” donde la densidad de población es varias veces mayor:

“Debido a la altura y la dificultad para llegar ahí, además de la exclusividad del sitio para investigación específica, ésta no sería accesible a nuestros visitantes. Más adelante en la temporada, antes que llegue la primavera, al menos una parte o tal vez la mayor parte de esa población se baje y se una con esta población menor de aquí. Podríamos tener entonces un gran Febrero,” seguraron los ejidatarios a Estela.

Las temperaturas se elevan de forma drástica día con día alcanzando los 20 grados celcious e incluso arriba si nos dirigimos más al sur; la intensidad del sol puede lastimar a vista, lo que probablemente sea razón de irrupción y de cierta conducta demasiado activa en nuestras Monarcas.

Por la noche, en contraste, las temperaturas caen drásticamente a congelantes, especialmente en los Santuarios de Sierra Chincua y El Rosario, fenómeno típico a medida que se acerca el invierno.

Por ahora, todo parece que la temporada evoluciona al punto de la normalidad y que las colonias en cada Santuario presentarán cambios normales a medida que avance la temporada, a menos que un evento repentino de clima pudiera modificar la condición actual. 

Visitar los Santuarios de las Monarcas en el centro de México resulta una oportunidad para disfrutar la excepcional gran migración; ha de ser también la oportunidad para reflexionar en singular agradecimiento por merecer ser testigos de este milagro de vida y por el milagro de la naturaleza hasta como la humanidad conocemos de ella hoy.

Estela Romero is an environmental educator with Monarchs Across Georgia. Reporting from Angangueo, Michoacán, Estela Romero's work is made possible by funding from Monarchs Across Georgia and the Monarch Butterfly Fund. Estela Romero es educadora ambiental de Monarchs Across Georgia. Informando desde Angangueo, Michoacán, el trabajo de Estela Romero es posible gracias a la financiación de Monarchs Across Georgia y el Monarch Butterfly Fund.