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The 2010 Breeding Season: the Latest

Last updated 03 September at 14h30.

TOADS ARE ACTIVELY BREEDING AT YOUNGSFIELD, ROYAL CAPE AND LITTLE PRINCESSVLEI. ACTIVITY HAS SLOWED DOWN WITH RESIDUAL ACTIVITY AT TOKAI (MORE DEATHS), THE CYCLE TRACK AND SWEET VALLEY!

Here we summarise the activities of the Volunteers in the different groups. Results are for two types of work: Rescue Work Monitoring If your group is not here then WHY NOT? Or if you would like to see past years then look at our history.

The 2010 Breeding Season: Progress

Historically feeding activity lasts for a week to a month before breeding begins (see Bergvliet history.). The toads are actively feeding and in wet weather they feed from the roads, where snails, slugs, earthworms and other delectables are easily seen. This is also a period in which many deaths occur as most toad groups are not ready with their campaigns yet.

Theories about the toads breeding (or triggered to breed) at Full Moon or with lots of rain are thus all out of the window. The toads that have bred so far have done it in dry weather at near New Moon. Obviously we need lots more data before we can understand what makes a toad breed!

This year has been unusual in that there has been so little synchronicity between the different breeding areas. Any theory as to breedign being caused by global effects such as the moon or rainfall or temperature are thus unlikely, with local (micro-) temperatures and rainfall, and other local effects such as water tables, food resources, pond levels and chemistry being far more likely. But it is still to early to know: we need lots more data before we can start unravelling our toads.

Take a look at the sex graphs for Die Oog and Bergvliet where volunteers have been recording the state of female toads as well. There is a clear pattern of males arriving first, followed by females full of eggs, after which the empty females leave, after which the males leave. The Die Oog team has also been recording if toads are arriving or departing, and the results are spectacular: as you would expect, but with enough exceptions to get one thinking! Keep it up!

Here are the daily sightings of toads by the different groups over the breeding season so far:

Rescue

Each group consists of volunteers who patrol the streets on dark rainy nights, and even many other nights during the breeding period. The total time spent on rescuing toads is often not appreciated. Here are the man-hours spent patrolling by the different volunteer patrols to date this year:

Here are the numbers of toads saved by each patrol this year:

Note that some areas are busier than others. Our goal is to ensure that we have enough volunteers to keep down the death rates. These data also allow us to plan for the hotspots next year.

In addition to rescuing toads, volunteers usually take their photographs. This is done carefully with a ruler in a standard pose. Toads' markings are like fingerprints. This allows toads to be compared from year to year, and thus estimates of age, distance moved and population size to be calculated. For more, and to put your own garden Western Leopard Toad onto the database, please see: upload your toad. For lots of toads it is better to submit a CD of photos see Guidelines for Data Collection. Here are the numbers of photographs taken by each patrol this year:

Status

Action by volunteers consists of three activities: 1) rescuing toads crossing roads; 2) collecting killed toads; and, 3) noting other toads not rescued or killed. (For our purposes, we consider injured toads to be rescued, unless we know that they have died, in which case they are "dead")).

The daily rescued/killed/noted toads for each group can be seen here.

Choose a group for the status of toads over time in an area:

Overall it can be seen that something exciting happened on the 21st of July, but what? It did not result in breeding. Breeding in the Noordhoek and Kirstenhof areas then took off, peaking in early August, followed by a second breeding event, in Tokai, Bergvliet, Constantia and Kenilworth, peaking about a month later. Is this it? Or will another attempt follow in the remaining areas. Most deaths concided with the peak runs, but the first peak in July caught volunteers by surprize resulting in much road kill. Both peaks were followed by a first very active day with a "rest day" before activity continued at high levels: are these artifacts or some real phenomenon? The seem to have lower death rates too!

Summary of Roadkills

Here is the proportion of toads killed in the different regions. Noordhoek (18% kill rate, 72 killed) has been surpassed by Tokai (29% kill rate, 37 killed) as the leading hotspot. The other hotspots are Kirstenhof (5% kill rate, 36 killed) and Bergvliet (3% kill rate, 23 killed)

Anything above a 15% kill rate is probably not sustainable. (It is difficult to give a sustainable rate as dead toads wait to be picked up, but live toads move off, so the actual mortality rate is much lower than the "kill rate" (toads killed versus toads rescued + killed).

Sexes

When rescuing toads volunteers collect demographic statistics. This is simply are the toads: Male, Female (in eggs {plump, on the way to breed}, without eggs {finished breeding or not breeding, often thin}, breeding state unknown), Sex unknown, Juveniles (less than 75 mm long) and Toadlets (less than 15 mm long). Toadlets are not usually seen during the breeding season, and Juveniles do not normally migrate to the breeding ponds, but are sometimes encountered. It is important to note if the Females are full of eggs and going to the ponds to breed, or if they are thin and finished breeding. As a rule Females migrate en mass to the ponds, but then sneak back home afterwards, so that most Females rescued are in egg. The categories Unknown are difficult to tell cases, beginner volunteers still finding their feet, and heavy workloads where numbers overwhelmed the volunteers. Sex statistics collected by the different volunteer groups can be found here.

Choose a group to look at the sex ratios over time for an area:

Overall the difference between the two breeding peaks (ignoring 21 July as an anomaly) differ markedly in how the females were far more prominent in the second peak. Whether this is due to some difference in volunteer rescue patterns between the groups (e.g. collecting earlier or being swamped by satellite males returning to the roads), or a real result will need further attention. The second breeding attempt was done by volunteers who separated females into those with eggs and those without and thus the females "arriving" (gravid: with eggs) and "leaving" (empty) can clearly be seen on the graphs. (arriving and leaving is not strictly correct, as volunteers also recorded direction of movement and some gravid females left and some empty females arrived, but these were the minority). Note that the "second day dips" are not simply that the males arrive first at the ponds and then call the females: females came in the first days as well.

Monitoring

Monitoring involves visiting the ponds and recording breeding activity. The location of known breeding ponds is shown here.

It is also important to note when there is no activity. Many groups are routinely visiting their ponds, monitoring when breeding begins and ends: the manhours for the different groups are shown here.

Activity over the season in the different pools is shown here.

Herwith is a summary of the activity to date. Ponds recorded as breeding sites are outlined in blue. Those active in the Past are in shown as red logos, those currently active (27 August 2010) in green and those about to start in yellow.

The highest numbers recorded so far are 200 toads in Die Oog on 24-27 August; 110 toads at DeVilliers2 and 85 at Raapkraal Central Pond on 05th August; 50 on 5th August at Arum Lily Pond (Raapkraal), from Swaanswyk on 28-30 August, and the Cycle Track on 30th August; 25 from Strawberry Lane on the 28th August; and, 15 at the Duckpond (Raapkraal) on 04-05 August. Other data tend not to give numbers of toads calling unfortunately, so we cannot quantify what has happened there.

Several pools around Noordhoek have been recorded as having eggs - it is usually about 2 weeks before tadpoles emerge. Eggs have also been observed in the Porter Estate (Tokai).

Tadpoles have been recorded from Kirstenhof and Noordhoek.

Cannot find your data here?

Did you send it through to us? Please use the SUMMARY DATA FORM and email your data before 08h00 if you want it included here. See GUIDELINES FOR DATA COLLECTION on what needs to be done.

HISTORY

Interested in what happened in previous years?

2009 Breeding Season

2008 Breeding Season

2007 Breeding Season

Regional Reports

2008/9 Bergvliet

2004-7 Bergvliet