Tuesday, April 13, 2021

Dolphin Births Later Than Usual This Fall

Stepping Stones

Photos by Bob McConville | Avery with her new calf Stefin. This little one was born the first week of November 2020, later than usual for mom Avery.


 

A very Merry Christmas and Happier New Year to all of you from the entire Dolphin Explorer and Wild Florida Ecotours teams. May all of your dreams and wishes come true, may all of you be blessed with good health and may all of your dolphins be smiling! Thank you for your continued support! ~ Bob 

As I write this article on December 18, 2020, I can tell you that a new baby dolphin was seen just 2 days ago, and it was no more than 4 days old. I know the age because we saw its mom just 5 days ago with no calf by her side. In early November, another adult female dolphin was seen with a new calf that was also less than 1 week old. These mothers are well experienced and both of them have given birth multiple times. The thing is, their other calves were all born in September. Why are these 2 new babies born a few months later? I think I have an answer. 

First of all, welcome to the world, Cubbie, the new offspring of mom Halfway. 

This female is one of my favorite dolphins that live in the north Marco area. She is a baby machine, giving birth every 3 years like clockwork since 2004. The Dolphin Explorer dolphin study team did not begin its survey of these local cetaceans until February 2006, but mom Halfway already had a calf by her side that was judged to be nearly 1 ½ years old. That would mean that it was born in the Fall of 2004. 

For the sake of clarity, dolphin calves will stay with the mother in this section of the world for nearly 3 years, and sometimes longer, before they go out on their own. Mom can become pregnant when a calf by her side is 2 and the pregnancy period is 1 year. If mom has a new baby when the calf by her side turns 3, that calf will leave mom and will now be called a sub-adult. Sometimes the calves will leave mom a few months before she gives birth to the new baby. 

In the case of the female Halfway, she has given birth in 2004, 2007, 2010, 2013, 2016, 2019 and 2020. Cubbie is her 7th calf known to the research team. But, wait! The math doesn’t quite make sense. There are regular 3year gaps between births except for 2019 into 2020. The reason being that her birth in 2019, Ben, did not survive. We only saw Ben for just over a month before he disappeared from the scene. There are predators in the water and Ben was a victim of one of them.

 


Almost 4 weeks old, Stefin kept up with mom Avery and is learning to swim quite well by mom’s side.


 

See that tiny fin next to female Halfway? This is Cubbie, born about December 15th of this year, and is the 7th known calf of this very productive mother. Good luck, Cubbie!

Almost immediately after Ben was gone, Halfway was being followed by two of the area adult males named Hatchet and Capri and they followed her for several months. With no calf to care for, Halfway would be open to mating again. With a pregnancy period of 1 year, she obviously conceived late last Fall, giving birth to Cubbie around December 15th. This period when she lost Ben in 2019 until the birth of Cubbie recently is the first known time that Halfway has been alone in 16 years.  

In the case of our other female Avery, she gave birth to Stefin in early November. She, too, is a mom that has consistently given birth in early Fall in previous years. Her other offspring were born in 2006, 2009, 2013 and 2016. Nothing seems very inconsistent and giving birth every 3 to 4 years is typical of many of our females. However, there is one peculiar point of interest that was observed.  

As stated above, many calves will leave their mothers’ care at 3 years old and sometimes sooner. This was the case in the Summer of 2019 when her 3-year-old named 360 when out on its own. This gave cause to suspect that Avery was pregnant. However, no new calf was seen in the Fall of 2019. In November of 2020, Avery gave birth to Stefin, rather late in the year for a typical Avery birth. 

I’ll repeat that no new calf was “seen” or documented in the Fall of 2019. There is a possibility that Avery had a calf and it was never physically noticed and therefore never documented. This could explain the late birth this year. 

So, there it is, two of our most productive adult female bottlenose dolphins giving birth in late Fall, far from the typical normal pattern. There are other stories to share from previous years plus stories of survival and success in our area, but they, my friends, are tails for another time! 

Wishing all of you success and happiness throughout your lives!

 



STEPPING STONES ADDENDUM 

On December 23rd, and then again on Christmas Eve, the Dolphin Explorer study team and some guests saw Halfway and Cubbie near Channel Marker 33 along the Intracoastal Waterway, behind Keewaydin Island. This is about 4 miles north of Halfway’s known territory for raising her young. 

These two were accompanied by another female named Nibbles that gave birth to Murphy earlier in the Fall. Nibbles is a unique story. She raises her young in the area described above, behind Keewaydin Island. However, she gives birth on the east side of the Jolley Bridge! That’s quite a journey but very typical for her.  

Previous calves of Nibbles, namely Jayson, Coco and Ollie were all born as noted above, then moved with Nibbles after a month or two of life and raised between Markers 33 and 48. If she maintains this pattern, Nibbles will be down by the bridge in 3 or 4 years to give birth again. 

Does Nibble move her offspring to provide better protection from predators for her young? Is Halfway following suit with Cubbie to assure the survival of her new calf? Only time will tell, so stay tuned for updates. 

New babies to ring in the new year! Happy New Year to all of you humans as well! 

Bob is a Naturalist for the dolphin study team on board the Dolphin Explorer and enjoys the Port of the Islands adventures with Wild Florida Ecotours. He is an award-winning columnist for Coastal Breeze News and the author of two books. Most of all Bob loves his wife very much! Merry Christmas Honey!!! 


 

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