The Cervid Project

01/06/2022

The rut, until next year my friends!

What initiates the rut?

For temperate deer, estrus is a consequence of decreasing day length (Lincoln and Short 1980). The pineal gland is most active in darkness, which produces melatonin. Shorter day length = more active pineal gland = more melatonin produced. Once a critical level of melatonin is reached, hormonal events leading to estrus are induced (Ditchkoff 2011). The reality is that deer need to give birth at a specific time of year for optimal survival of offspring (Asher 2011). Obviously, day length is a far more reliable cue than moon phase which cycles monthly and temperature.

Here are some cool experiments that settled it:
An experiment where deer moved across the equator resulted in an exact 6-month change in the estrus cycle, definitely showing that estrus was cued by the shortening of photoperiod and not photoperiod length itself (Marshall 1937). Note this study was published 85 years ago! Ever heard that in healthy populations fawns will breed? That is true, but it isn’t the whole story. Fawns raised in a room where photoperiod was precisely controlled experimentally for 9 weeks showed that estrus was delayed when photoperiod was maintained stable in “long” days (Verme and Ozoga 1987). A long term study on hundreds of wild deer in VA showed that conception during the fall was completely independent of temperature in weeks leading up to conception, moon phase, or other weather (McGinnis and Downing 1997). However, the nutritional status of females leading into breeding season did matter based on summer forage availability. Healthier does tended to be the first to go into estrus. Thus, improving summer nutrition and balancing density with habitat tends to synchronize breeding, slightly earlier in fall (DeYoung and Miller 2011).

Better habitat = intensified rut!

References:

- Asher, G.W., 2011. Reproductive cycles of deer. Animal Reproduction Science, 124(3-4), pp.170-175. https://www.researchgate.net/publication/47155811_Reproductive_cycles_of_deer
- DeYoung, R.W. and Miller, K.V., 2011. White-tailed deer behavior. In Biology and management of white-tailed deer (pp. 324-367). CRC Press. https://www.taylorfrancis.com/chapters/edit/10.1201/9781482295986-14/white-tailed-deer-behavior-randy-deyoung-karl-miller
- Hewitt, D.G. (Ed.). (2011). Biology and Management of White-tailed Deer (1st ed.). CRC Press. https://doi.org/10.1201/9781482295986
- Lincoln, G.A. and Short, R.V., 1980, January. Seasonal breeding: nature's contraceptive. In Proceedings of the 1979 Laurentian Hormone Conference (pp. 1-52). Academic Press. https://www.sciencedirect.com/science/article/pii/B9780125711364500073
- Louis J. Verme, John J. Ozoga, Relationship of Photoperiod to Puberty in Doe Fawn White-Tailed Deer, Journal of Mammalogy, Volume 68, Issue 1, 27 February 1987, Pages 107–110, https://doi.org/10.2307/1381052
- McGinnes, B.S. and Downing, R.L., 1977. Factors affecting the peak of white-tailed deer fawning in Virginia. The Journal of Wildlife Management, pp.715-719. https://www.jstor.org/stable/3799994
- Sumners, J.A., Demarais, S., Deyoung, R.W., Honeycutt, R.L., Rooney, A.P., Gonzales, R.A. and Gee, K.L., 2015. Variable breeding dates among populations of white‐tailed deer in the southern United States: The legacy of restocking?. The Journal of Wildlife Management, 79(8), pp.1213-1225. https://doi.org/10.1002/jwmg.954

01/02/2022

Couldn’t agree more

Necropsy is a fancy term for digging into a co**se in order to, in most cases, figure out the cause of death. For deer hunters who are elbow-deep in a dead buck, it might seem like the cause of death is pretty easy to pin down. You shot it with an arrow or a bullet, and that’s that. It’s not alw...

12/31/2021

Have you been seeing any bucks dropping early this year?

Although it was warm for December, I couldn’t help but shiver as the whitetail’s rack grew wider with each step closer. At 130 yards, I battled through buck fever and touched off a shot. Blaukš! The deer dropped in its tracks. I quickly gathered my gear and set off to claim one of my biggest bu...

12/05/2021

That’s more like it.

As cooler weather arrives and the rut approaches, adult buck movement increases and now we have three peaks in daily activity.

A month before the rut (gray line), there was only one distinct peak in buck movement on our study area in central Mississippi: right at sunset. But with cooler weather and the generally increasing movements associated with the approaching rut, a second and third peak in movement are evident (black line).

Chances of seeing an adult buck on his feet were greatest in the evening a month ago, but now it’s a coin toss between morning and evening. And, don’t even think about taking advantage of that nighttime peak!

These movement rates will continue to increase over the next several weeks to the point that you should probably just call off work and be in the woods all day...

*The black line is shifted left because of daylight savings time change.

08/24/2021

Interesting buck

A buck in a South Delta deer study crossed the Mississippi River and spent spring and summer in Louisiana. He's crossed the river again and returned.

07/20/2021

Will definitely be interesting to follow and learn more about!

Supplemental feeding: increased nutrition, increased wildlife sightings, and increased disease?

Supplemental feeding is a popular management activity, but there are concerns that it may negatively affect wildlife health. To see if this is true, the MSU Deer Lab spent the past 3 years studying the relationship between deer feeders and disease. We looked at gastrointestinal parasites, aflatoxins, and more.

Stay tuned in the upcoming days as we share some of our most interesting results with you and provide tips to help keep yourself and wildlife healthy.

07/20/2021

Lesson here is staying close to where they bed will likely give you a better opportunity to see a buck during daylight.

07/19/2021

The three most dreaded letters of deer hunters E…H…D… Many hunters across the country have seen the impact of EHD on local deer herds and it is sickening. When XYZ number are reported and confirmed people start to think it’s not that bad. But that number is a mere percentage of what has actually been lost. Warren and Lucas counties in Iowa had 75-90% loss in many pockets 2 years ago. Is there anything we can do to help prevent major losses like this in the future? The answer is maybe, after talking to many deer farmers, vets, and biologists there may be a way to help your local herd. Check out how here:

https://iowawhitetail.com/threads/ehd-management-tactics.60466/