# swarming and growing degree days



## squarepeg (Jul 9, 2010)

Riverderwent said:


> So I've been playing with the growing degree days calculator. I've got a couple of thoughts. One is that the key date may be a few days or even a week or two before the actual swarm date, when the queen is put on a diet and training plan to get her in shape for the exodus. Two is that the 50 degree base growing degree days seems a little more erratic that the first swarm dates here. But after this winter, I'm not as confidant of that. Common sense would say that there is a link.


i've been playing with some of the reports from the 'post your swarm dates' subforum. gdd's are ranging from 400-700. you may be right about it being too erratic, but perhaps useful in terms of when to set out swarm traps, start paying closer attention to the hives, ect.


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## Riverderwent (May 23, 2013)

squarepeg said:


> i received a prompt reply from the new jersey beekeeper. he's sending me a power point presentation on their results.
> 
> as it turns out, (and not too unexpectedly) the growing degree days correspond nicely to the bloom dates that we have been associating with swarming.
> 
> gdd may be just another interesting metric to pay attention to with respect to predicting colony operations as the season progresses.


When you get the powerpoint, I'd like to hear about what it shows.


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## squarepeg (Jul 9, 2010)

squarepeg said:


> before walt's passing he was in communication with a new jersey group that was looking carefully at growing degree days and attempting to relate that to the starting and stopping of swarming.


david, the new jersey beek sounds really fired up about their results and is supposed to send me the power point and related info soon.


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## Steve in PA (Jan 26, 2015)

I was just discussing this with a beek friend the other day. Not just swarming but other bee-related events and relating them to GDD. I make a lot of SQL tables and forms to store data and plan to do the same with my hives this coming year using QR labels and my cellphone during inspections.

I have no idea what I will find but I know that good data and records are never wasted.


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## squarepeg (Jul 9, 2010)

very cool steve, please keep us posted on how that turns out.


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## herbhome (Oct 18, 2015)

This looks like an encouraging line of inquiry.


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## Steve in PA (Jan 26, 2015)

I do wonder if some of the erratic measurement was because of the temps they were using. 50/86 may not work for what we are trying to see and changing that would tighten up the 400-700 range. The one at Upest.org defaults to 50/95 but you can change it. Since that one is based on agricultural pests, many of which are insects, maybe that one would be more useful?

Putting my location into http://uspest.org/cgi-bin/ddmodel.us says my location is 1 day ahead of last year, 37 days ahead of 2015, and 50 days ahead of the 30-year normal. I'm trying to figure out if they mean actual days or degree days in that statistic.


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## squarepeg (Jul 9, 2010)

good question. i've invited the new jersey beek to join our discussion if he is so inclined. in the mean time i'll have to do a little homework to understand what all these numbers actually represent.


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## MonkeyMcBean (Mar 1, 2017)

Steve in PA said:


> I make a lot of SQL tables and forms to store data


I've wanted to be able to do this for a long time. Can you recommend a good place to learn? My Google searches come up unhelpful.

Sorry to be off topic,
Cliff


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## gww (Feb 14, 2015)

I wasn't smart enough to figure out you guys caculators and so found one and picked spring wheat as the product. 

We are over 200 gdd from last year at like 461. last year was 100 gdd more then 2015 at 200 something gdd. and the last warm year before that was over 200 gdd was 2013. 2014 and 2015 were at about 98 gdd.

At least for growing spring wheat We are warmer this year where I am.
Cheers
gww


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## Rader Sidetrack (Nov 30, 2011)

>> I make a lot of SQL tables and forms to store data.



MonkeyMcBean said:


> I've wanted to be able to do this for a long time. Can you recommend a good place to learn?


One option is to acquire a $35 Raspberry Pi 3B and go for it. Install Raspbian OS (a Linux variant), SQLite, Nginx (a web server) and phpliteadmin.php. That may sound like a complicated project, but just go one step at a time. Using a Raspberry means there are no permissions restrictions (such as there are on a 'normal' phone device), you can easily make the Raspberry control external devices if you like, and there is a LOT of software and help available. More here: https://www.raspberrypi.org/. One neat feature of a Pi is that if you get things hopelessly messed up, swap in a different SD card (start from your backup) and reflash the screwed up card for reuse.  Its no big deal to reflash the SD card, and there is not the anxiety often associated with a _hosed_ PC (requiring reloading of the operating system).

I see that _squarepeg_ mentioned data from Wunderground.com above. One neat (free, if your daily requests are less than 500 requests) service they offer is complete daily forecast information, localized for _your_ zipcode, in an easy-to-use data exchange format (XML or JSON).
https://www.wunderground.com/weather/api/

If the above sounds interesting, tie it all together with a free weather station software. Weewx, which coincidentally, can run on on a Pi with SQLite, and Nginx. Weewx is most useful for managing data from a home weather station with USB data interchange capability. The Accurite 01036 can be had for around $99, for example.

While 'weather' data is the tie to beekeeping and this thread, you can use the Pi with SQLite & Python for virtually _any_ kind of data oriented task. After getting my first Pi in October, I now have 3 Pi doing various tasks. 

.


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## Steve in PA (Jan 26, 2015)

Rader Sidetrack said:


> I see that _squarepeg_ mentioned data from Wunderground.com above. One neat (free, if your daily requests are less than 500 requests) service they offer is complete daily forecast information in a data exchange format like XML or JSON.
> https://www.wunderground.com/weather/api/


Thank you! I have looked for a place to get data in that format for a long time. Currently I'm tracking egg production in our chickens in the same way I want to apply to the bees. Importing temperature data is 2 less (daily high/low) items that will need user input.

I bought a Pi3 last year but have not had time to dive into it yet. I want to build a mesh network with a Pi3 hub and Pi Zero's as collection units in each individual hive to automate the entire process. A big task when I barely have enough time for other more pressing items.



MonkeyMcBean said:


> I've wanted to be able to do this for a long time. Can you recommend a good place to learn?


I'm self taught out of necessity over the years. Best I can say is start here. Create a simple form then look at the source code for it and break it down. Understand what it is doing and why. Once you do that you're 90% home.


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## squarepeg (Jul 9, 2010)

found this today:

"Published on Apr 11, 2015

Charley explains his approach for swarm management and his technique for using growing degree days and other factors to gauge when to take action on swarm prevention including the Walter Wright checkerboarding concept."

https://www.youtube.com/watch?v=WPTbDBpx-3s


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## R_V (Aug 20, 2016)

following... I use Rasp Pi's for several task including ad blocking DNS server and OSMC media center to name a couple. they're cool little do-dads.


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## squarepeg (Jul 9, 2010)

a lot of charley's presention is discussing checkerboarding, but with respect to gdd he's determined that the time for checkerboarding should be at about 50 gdd.

for my location 50 gdd happened during a warm spell we had in mid january, which also happened to be when foraging for the first tree pollens started, and when the first rounds of brood got underway.

i ended up checkerboarding a few weeks later as time and weather permitted, at just over 100 gdd, and at which time the colonies were well into their second round of brood and clearly expanding the broodnest.


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## minz (Jan 15, 2011)

This method is done for determining when to spray trees from everything to fungus to apple moths. The attached link from OSU (Oregon state) shows models, weather pages and more information than a person could digest in a four year degree program. It tells what pest (or insect) in your given weather station is hatching based on growing degree days, rain ect. 
http://pnwpest.org/
the top link has a good tutorial of how to use the info. I do not know if it works for you out of state guys. 
They may already have the model you are looking for in one of the drop downs.


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## Beebeard (Apr 27, 2016)

GDD might get us to the first swarms, but all the hives in an area don't swarm all at the same time, for better or worse. The first swarms will be from the strongest hives. I have 9 hives and know which one will be first this spring, and a good idea of which ones will follow. I watch the GDD closely here: https://www.oardc.ohio-state.edu/gdd/CalendarView.asp As of this week we are ahead of the last 3 years combined, ridiculously ahead.

I wonder whether following the GDD + flying days from first pollen flow (maple here) would be more accurate. Pollen is what kicks up the brood rearing, and some kind of matrix that follows the pollen availability with forage temps and brood development math might be most accurate. Then again, popping a lid on your strong hives will give the best results.


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## squarepeg (Jul 9, 2010)

Beebeard said:


> I wonder whether following the GDD + flying days from first pollen flow (maple here) would be more accurate. Pollen is what kicks up the brood rearing, and some kind of matrix that follows the pollen availability with forage temps and brood development math might be most accurate. Then again, popping a lid on your strong hives will give the best results.


good post. what might confound the interpretation of gdd vs. swarming is whether or not pollen sub and syrup was applied during the build up.

generally what i've noticed is that the swarm reports start coming in first from down around florida and the gulf coast and then gradually work their way north.

it makes sense that has to do with temperature which drives bloom dates, so it will be interesting to see how closely gdd correlates with all that.


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## 1102009 (Jul 31, 2015)

Since we ( my small tf group) found a way to bait legally I´m very excited about swarming.
https://www.mellifera.de/blog/freibeuter...lockkisten.html
Started my wax moth-breeding "hive" today to have bait material, I still had some brood comb left.

Squarepeg, do you remember the former member Sulz on Viva?
He talked about the different kind of swarms.

so.
1.- reproduction swarm...this is what this thread is about.
2.- hunger swarm....bees swarming because too many hives are placed in a location without providing enough food for all.
3.- escape disease swarm....swarms which leave because of disease impacts.

Different reasons---different times.
To all: what is your experience? Do you always know the reason your colonies swarm?


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## squarepeg (Jul 9, 2010)

sorry sibylle, i don't recall viva member sulz. 

most of mine have been reproductive swarms, based on the time of the year and observations made inside the hive.

occasionally i have a very small swarm issue in the fall, which i assume has more to do with supercedure and the old queen leaving with a small number of bees loyal to her.

i'm happy to hear that you will be able to trap swarms there!


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## squarepeg (Jul 9, 2010)

https://academic.oup.com/ee/article-abstract/47/3/603/4958150?redirectedFrom=fulltext

(abstract only, full paper is behind a pay wall)


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## Steve in PA (Jan 26, 2015)

Interesting...the abstract says they found little corellation with GDD.


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## squarepeg (Jul 9, 2010)

yes, it appears the nj bees are more in tune with the calendar than they are with gdd.

i have the full paper, and in it there is a histogram of the dates of all the swarms reported.

(i'll try to get permission to paste a screen shot of it on the forum)

the histogram is a tight bell curve centered up on the may 15 date +/- a couple of weeks.

this gives some support to walt wright's contention that there is a point in the season at which colonies 'turn the corner' on swarm ambition. a couple of walt's papers are cited in this study.


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## clyderoad (Jun 10, 2012)

what gdd base temperature was used?


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## squarepeg (Jul 9, 2010)

50 degrees f and starting january 1 each year.


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## clyderoad (Jun 10, 2012)

I would think that conclusions based upon a 50 degree base, mostly used for a agricultural base, would not be as useful as the 32 degree base for this purpose. 
The earliest pollen and nectar sources for our bees are available well before the 50 degree base registers any meaningful heat accumulation ie soft maples, skunk cabbage, some alder and elder, some witchhazels- non agricultural plants that may set the stage for swarming. 
Maybe the researchers have explained the reasoning behind utilizing a 50 degree base instead of a 32 degree base, but maybe not?


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## squarepeg (Jul 9, 2010)

the reasoning for choosing the 50 degree base was not discussed.


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## squarepeg (Jul 9, 2010)

dr. gilley graciously responded to my email request regarding his recent paper linked in post #22. here are a couple of snippets from his reply:

"...for these data, taking into account GDD did not reduce the uncertainty of our estimate of the mean swarm date. That should not be interpreted as there being no correlation between GDD and swarm date, but that the causation that explains the correlation is indirect rather than direct..."

"I think you’re right about the reproductive cutoff. It’s something I had also seen in my previous attempts to study queen fighting in observation hives in mid-summer … they won’t do it! But I was surprised about how reliable that cutoff seems to be in this New Jersey data, despite that these three years were quite variable. It suggests to me that the cutoff is under significant selection pressure, in other words it’s a pretty bad idea to swarm either too early or too late."

dr. gilley also told me it was alright to post the histogram displaying the raw data along with giving proper citation:











from: Gilley DC, Courtright TJ, Thom C (2018) Phenology of honey bee swarm departures in New Jersey, USA. Environmental Entomology 47(3):603-608.


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