Archivos de Diario para marzo 2020

08 de marzo de 2020

The Living Landscape: The forest sharp-tailed snake.

This secretive, slim snake is non-poisonous and can be found in damp, forested areas throughout Northern California, southern Oregon, and as far north as British Columbia, mainly along the North Coast areas.

Anotado en 08 de marzo de 2020 a las 10:41 PM por biohexx1 biohexx1 | 0 comentarios | Deja un comentario

27 de marzo de 2020

Alligator lizard mating

Post from @gregpauly

Love in the Time of Coronavirus: The Alligator Lizard Version*
With days getting longer and temperatures increasing, we are entering alligator lizard mating season, and we need your help to study their mating activity.

Five years ago, we realized that we could use crowdsourcing as a way to study mating behavior. At that time, there were only three dates reported in the scientific literature for when Southern Alligator Lizards had been observed breeding. We knew we could get more observations through community science, by crowdsourcing the study of this rarely documented behavior. We started asking people to send us photos and videos of mating pairs. We have now accumulated 360 observations of mating Southern Alligator Lizards, and 57 observations of mating Northern Alligator Lizards. We are pretty sure that through community science, we have generated the largest dataset ever on lizard mating!

What does mating behavior look like? Typically the male is biting the head and neck region of the female as you can see in these previous observations of mating behavior submitted to the RASCals project: (observation by @janegao) (9% of observations involve multiple males and a female)

What have we learned with all these observations? Here are three discoveries so far.

  1. Weather has a huge impact on the timing of the breeding season. Cooler and wetter weather will delay the start of the mating season. If mating activity has already started, then bigger storm systems can shut down activity until weather improves. We received six observations of mating activity for the 2020 season, but then the cooler mid-March weather in Southern California shut the season down. As temperatures increase again through late March and April, the mating season should rapidly progress, although it is now delayed by several weeks across Southern California relative to more typical years. As forecast, after more than two weeks with no mating observations, the season is finally ramping up with three observations just on March 26th!
  2. Wet years are the big breeding years. Although we started this research effort in 2015, people have submitted observations that date back to 2003 (woohoo for digital cameras!). Across these years, we see that drier years have reduced breeding activity. For example, the 2015, 2016, and 2018 mating seasons followed below average rain seasons, and we received 32–35 observations of Southern Alligator Lizards in the mating position. But following the wet 2017 and 2019 winters, we received nearly three times as many observations! The 2020 season is only just getting started in late March (all observations are still from the very southern end of the range), and it is especially hard to predict whether this will be a good or bad year. For much of California, the rain season started off with above average rainfall in December but then the state experienced an extremely dry January and February. We are now having enough rain that people are talking about another “Miracle March”, but this rain might be too late to trigger increased breeding activity. As observations get made, we’ll be able to better understand how the timing of rainfall impacts breeding activity.
  3. Lizards can stay paired up for over two days! The actual act of mating likely takes place shortly after the lizards pair up. However, the male maintains the bite hold for a long time. This is most likely a type of “mate guarding”, in which the male is trying to make sure that no other males can mate with the female (but we still have more research to do before we are positive this is what’s happening). But how long might a male maintain the bite hold? In 2019, two dedicated community scientists (@molly91945 and @lemonbee) repeatedly checked back on a pair and observed the lizards together for nearly 49 hours! This is a new record for this species!

What to look for? During mating season, males search out females. The male bites the female on her neck or head and may hold her this way for several days. Early in the encounter, the two may engage in a bit of a wrestling match (if you see this, please try to get videos). Sometimes, a second male shows up and we get even more interesting observations!

When to look? Because we have accumulated so many observations, we now know that the Southern Alligator Lizard mating season can start as early as early February in the southern part of the range and continues into early June in the northern part of the range and at higher elevations. In Southern California, most of the breeding activity is between mid March and late April. This year, the season is just getting started in late March, and mating pairs should be found in coastal Southern California through early May, with mating in more northern and higher elevation locations throughout May and June. For the Northern Alligator Lizard, breeding should start in early to mid April and continue through mid-June, again with lizards in the south and at lower elevation populations breeding earlier.

Where to look? Alligator lizards can be found from coastal sand dunes to high elevations in our mountains. And they do better than any other local lizard in urban areas. When in the bite hold, pairs are often found out in the open, on driveways, sidewalks, lawns, and in yards. It is also possible to find pairs several feet off the ground on fences and in shrubs.

How to document? Take photos! If the pair is actively wrestling, please take video as well. We are especially interested in how long pairs remain in the mating hold, so please check back every few hours and search for the pair in the general area.

If you see courting or mating alligator lizards, please upload photos to iNaturalist. If you are in Southern California, please tag observations to the RASCals project.

*With apologies to the late Gabriel Garcia Marquez for playing off the title of his excellent novel.

Anotado en 27 de marzo de 2020 a las 06:24 AM por biohexx1 biohexx1 | 0 comentarios | Deja un comentario